U.S. patent number RE28,506 [Application Number 05/514,750] was granted by the patent office on 1975-08-05 for indicia bearing anodized aluminum articles.
This patent grant is currently assigned to Horizons Incorporated. Invention is credited to Harold J. Quaintance, Eugene Wainer.
United States Patent |
RE28,506 |
Quaintance , et al. |
August 5, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Indicia bearing anodized aluminum articles
Abstract
The production and use of indicia-bearing anodized layers from
which the backing metal has been removed as transparent or
translucent elements in articles in which the layer may be
laminated to a clear or translucent layer so that the information
contained in the anodized layer can be read by direct illumination
rather than by reflected light. The information in the pores of
this anodized article is preferably in the form of a metal image
and of a metal selected from the group consisting of silver, gold,
platinum and palladium which is preferably silver and which may be
intensified by the electroless deposition of other metals thereon,
such metals being selected from the group consisting of nickel,
cobalt, iron, copper, chromium, gold, silver, platinum, palladium
and mixtures thereof. Products of special interest include edge
lighted panels, microfilm, microfiche, photomasks, and printed
circuits.
Inventors: |
Quaintance; Harold J. (Fairview
Park, OH), Wainer; Eugene (Shaker Heights, OH) |
Assignee: |
Horizons Incorporated
(Cleveland, OH)
|
Family
ID: |
26900478 |
Appl.
No.: |
05/514,750 |
Filed: |
October 15, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
205493 |
Dec 7, 1971 |
03765994 |
Oct 16, 1973 |
|
|
Current U.S.
Class: |
428/203; 427/437;
428/469; 428/320.2; 428/318.6; 428/418 |
Current CPC
Class: |
B41M
1/28 (20130101); G03C 1/77 (20130101); H05K
3/106 (20130101); G03C 5/42 (20130101); Y10T
428/249988 (20150401); Y10T 428/249994 (20150401); Y10T
428/31529 (20150401); Y10T 428/24868 (20150115) |
Current International
Class: |
B41M
1/26 (20060101); B41M 1/28 (20060101); G03C
1/77 (20060101); G03C 5/40 (20060101); G03C
5/42 (20060101); H05K 3/10 (20060101); B44F
001/06 (); B32B 015/08 (); C25D 005/00 (); G03C
001/02 () |
Field of
Search: |
;161/6,214,216,186
;117/211,13E ;96/38.4,86R,94,114.3 ;204/23,148 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dier; Philip
Attorney, Agent or Firm: Field; Lawrence I.
Claims
We claim:
1. A laminated article bearing an image buried within at least one
lamina of said article and comprising:
at least one clear supporting panel member;
at least one transparent porous layer consisting of aluminum oxide
at least some of the pores of which contain an opaque material
distributed in said pores so as to define an image;
and a clear adhesive disposed between said panel and said porous
layer and bonding said panel to said porous layer.
2. The laminated article of claim 1 wherein the opaque material in
said pores is a metal selected from the group consisting of silver,
gold, palladium and platinum.
3. The laminated article of claim 2 wherein the opaque material
includes an additional metal selected from the group consisting of
nickel, cobalt, iron, copper, chromium, gold, silver, platinum,
palladium and mixtures thereof deposited within the metal coated
pores.
4. The laminated article of claim 3 wherein the opaque material is
silver.
5. The article of claim 1 wherein the opaque material is a dye.
6. The article of claim 1 including at least one nonporous layer of
aluminum oxide covering said porous layer of aluminum oxide.
7. The laminated article of claim 1 wherein the clear supporting
panel is colored.
8. The article of claim 1 as a photomask.
9. The article of claim 1 as an identification badge.
10. The article of claim 1 wherein the buried image defines a
printed circuit.
11. The article of claim 1 wherein the adhesive is a bead disposed
between said clear panel and said porous layer thereby spacing said
panel from said layer.
12. The article of claim 1 wherein the transparent porous layer of
aluminum oxide is attached to a layer of non-porous aluminum oxide
with which it is integral.
13. The article of claim 12 wherein the layer of nonporous aluminum
oxide is supported on an aluminum metal base with which it is
integral.
14. A laminated article formed by laminating a plurality of the
assemblies of claim 1 in face to face relationship and into a
single package. .Iadd. 15. An article bearing an image buried
within at least one lamina of said article and comprising:
at least one transparent porous oxide layer consisting of aluminum
oxide, at least some of the pores of which contain an agent capable
of catalytically depositing conductor metals and an opaque material
deposited on said agent and said pores so as to define an
image;
a clear adhesive material disposed on said porous oxide layer and
filling said pores; and
a metal deposited in the pores of said porous oxide layer said
metal being deposited on said agent..Iaddend..Iadd. 16. The article
of claim 15 wherein the agent is a metal selected from the group
consisting of silver, gold, palladium and platinum..Iaddend..Iadd.
17. The article of claim 15 wherein the opaque material includes an
additional metal selected from the group consisting of nickel,
cobalt, iron, copper, chromium, gold, silver, platinum, palladium
and mixtures thereof deposited within the metal coated
pores..Iaddend..Iadd. 18. The article of claim 15 wherein the metal
in said pores is silver. .Iaddend..Iadd. 19. The article of claim
15 wherein the adhesive is an epoxy resin..Iaddend.
Description
The use of anodized aluminum in the production of highly durable
articles is well known. Such articles when properly treated exhibit
extremely durable properties, making them suitable for such objects
as residential siding, various trim or molding components for
automobiles, and in an extreme example have been successfully
employed as cylinder walls in the internal combustion engine.
Because of this durability characteristic, when properly treated
(sealed) together with a characteristic microporous nature in the
unsealed state, use has been made of anodized aluminum in the
commercial production of highly durable, abrasion resistant,
reflective photographically imaged articles composed of silver such
as defined in U.S. Pat. No. 2,766,119 or in conjunction with a
resist material as described in U.S. Pat. No. 3,079,309 disclosing
images consisting of various colorants or dyestuffs within the
porous anodized layer for the production of nameplates,
identification badges, dial panels, and a variety of other highly
durable objects which are suitable for use in extremely harsh
environmental conditions for relatively long periods of time,
especially when the photographic-silver images are toned with gold
and then sealed by any of the known methods for sealing anodized
aluminum such as referred to in U.S. Pat. No. 3,715,211 issued Feb.
6, 1973.
All of the known heretofore uses and techniques employing imaging
within the anodized layers are limited by the fact that the various
objects produced are necessarily viewed with reflected light since
the anodized layer is supported by the aluminum metal backing
member from which the anodized layer was produced and lends support
to the anodized layer as well as acting as a light scattering
medium which enhances the metallic vitreous effect characteristics
of such anodized layers.
It is also known to those familiar in the production of anodized
aluminum articles and well described in "The Surface Treatment and
Finishing of Aluminum and its Alloys" by S. Werneck and P. Pinner
that the anodized structure consists of micropores which extend
vertically toward the aluminum backing member, separated therefrom
by a thickness of anodized aluminum, commonly referred to as a
"barrier layer" which is integral with the aluminum backing member.
When such an anodized layer is removed from the aluminum backing
member and viewed under high powers of magnification e.g. by the
use of an electron microscope, this barrier layer can be seen to
consist of a continuous coherent layer of nonporous anodized
aluminum which is similar in every respect to a sealed anodized
layer being characterized by extremely good abrasion and chemical
resistance, weatherability characteristics, and refusal to accept a
dye or stain. Thus the anodized layer when removed from the
aluminum backing member and reversed, the barrier layer now facing
the viewer as the surface layer, is in every respect both
chemically and physically equivalent to a sealed anodized layer as
normally obtained, by sealing the porous anodized layer in the
usual way. Further, if an anodized aluminum article preferably in
the unsealed state (porous) is first coated with a cross-linkable
monomer or a thermosetting polymeric material, or a pressure
sensitive thermosetting or thermoplastic composition such that when
suitable energy in form of light, heat, or pressure or any
combination thereof is supplied, a polymeric coating is obtained
which preferably penetrates the porous anodized layer and bonds to
the same so that a sealed nonporous layer throughout said structure
is assured.
By the use of known solvents which exert a solvent action on the
aluminum metal backing member only and which have little or no
solvent action on the anodized aluminum oxide layer, the backing
member of the above polymer treated article can be
removed--resulting in an article which has all the durability
characteristics of a sealed anodized aluminum article and which, in
addition, can be viewed by transmitted light.
It is therefore the principal object of this invention to provide
novel products and methods, by which highly durable dimensionally
stable films or transparencies or other articles can be made which
have many uses and advantages heretofore unattainable and which
form the various objects and embodiments of this invention.
One specific object of this invention relates to the use of such
novel highly durable films in the manufacture of edge illuminated
panels, particularly to the production of such films which form
that portion of such panels known as the "indicia" panel, resulting
in a novel product of high utility.
Another object of this invention pertains to the use of such novel
highly durable transparent films in the production of microimaging
known as microfiche, with the advantage of great dimensional
stability in changing ambient conditions.
A further object of this invention pertains to the use of such
novel highly durable transparent films in the manufacture of
photomasks, again resulting in remarkable dimensional stability in
varying ambient conditions.
The fourth object of this invention pertains to the use of such
novel highly durable electrically insulating films as the basis for
the production of printed circuits.
The fifth object of this invention pertains to the use of such
novel highly durable transparent films in the manufacture of
lighted displays for information or advertising purposes.
The sixth object of this invention pertains to the use of
"electroless" plating techniques for imagewise increase of diffuse
transmission density of developed out and fixed silver images
embedded in an anodized layer on aluminum.
Edge illuminated panels generally comprise a clear transparent
sheet of glass or plastic such as acrylic or methyl methacrylate
resin upon one surface which contains white translucent indicia
outlined by an opaque black field. The means of illumination are
generally provided by miniature tungsten bulbs or by light emitting
diodes which direct light indiscriminately through the panel being
reflected from the opaque surface while illuminating those areas
consisting of the white translucent material which generally
defines the indicia. A variety of methods are available for
directing light efficiently throughout the panel since it is in
most instances essential that instruments or dials be viewed at
night. It is recognized that "dark adaptation," i.e. the maximum
ability to see in the dark before or after being exposed to strong
ambient light, is desirable in some instances and that red light
does not materially alter this adaptation phenomenon, hence the
illuminating source on many dials and instruments aboard ships and
aircraft will employ red colored illuminating sources and therefore
must be highly efficient since these are placed within or at the
edges of the light transmitting panel. So that no glare is given
off from the surface of such panels and to provide maximum contrast
when viewed with ambient external light, the indicia generally
consist of flat white translucent material and the remainder of the
panel a flat black opaque background coating, together which
comprise the indicia panel which is generally the most complex
portion of the system and expensive to fabricate.
Conventional edge illuminated systems generally utilize optically
flat, polished, transparent surfaces; one of which contains the
indicia panel laminated to the light transmitting panel and the
other or reverse side of which may be covered by the opaque black
field to conserve light energy. The indicia comprising the indicia
panel may be etched, painted, printed or engraved.
In order to eliminate difficulties caused by refracted images of
the illuminating source and parallax when the overall size of the
panel is restricted, a duo-panel system has been utilized wherein
the indicia panel is separated from the light transmitting panel by
a small air space which provides poor optical contact between two
panels. In this method suitable support of the indicia panel
without optically contacting the transparent element is difficult
at best.
A high ratio between daylight reflectivity of the exposed indicia
and the transmission of internal light compared to the opaque black
outline may be achieved by use of embossed or raised graduations of
the indicia formed in the light transmitting panel to which a
translucent white lacquer is applied, followed by a second thin
lamination of opaque black lacquer at the base and surrounding
areas, leaving the white raised portions free of opaque.
In direct contradiction to the principle of providing poor optical
contact between the indicia-bearing panel and the
light-transmitting panel, a concept may be employed whereby
polished metallic surfaces are optically bonded to the surfaces of
an edge illuminable panel and light is transmitted by reflection
between the polished reflective boundaries which may be composed of
polished metal foil, sheets, evaporated metal films or the like. A
translucent, white coating is then laminated over the foil while an
opaque, black coating is applied to the translucent coating. To
provide openings in the foil for the indicia or markings, the foil
laminated transparent panel can be coated with a photoresist and
metal selectively removed. Alternately, the patterned openings may
be filled with a translucent material or insert and the remaining
area blackened by chemical means or by painting.
In another mode the indicia panel may be formed with printed
circuits or other conductors for carrying electrical current to the
lamps whereby the circuits are pressed flush into the top and
bottom surfaces of the indicia panel, using heat and pressure. In a
second procedure, the electric circuits are formed by two
nonconnected wire mesh laminations embedded in the top and bottom
surfaces of the indicia panel or alternately the electrical
circuits are pressed flush into only the bottom surface of the
indicia panel, forming a separate line pattern.
In yet a further modification, the light-transmitting panel may be
completely coated with a white translucent coating followed by an
opaque flat black lamination. The black opaque coating may then be
scribed or mitered out, exposing the white translucent layer
thereby forming the indicia, providing both laminations are
carefully controlled with regard to thickness, both surfaces of the
light-transmitting panel being perfectly flat and parallel.
In order to obtain a polychromatic edge illuminated system, the
indicia may be formed with an inlaid mosaic of colored glass or
plastic spelling words while the light-transmitting panel contains
miniature lamps of various colors or enclosed in various colored
filters; the number depending on the number of colors or words
desired. As the various colored lamps are selectively energized,
any word or color in the indicia panel corresponding to that color
will be lighted; whereas colors complimentary to that color will
effectively prohibit light. In this manner a multicolor system may
effectively be displayed, depending on the number of different
colored filters or lamps and color-forming indicia employed. The
multicolor indicia panel may have a translucent or ground surface
or be assembled behind a neutral filter sheet to avoid ambiguity in
strong ambient light. The colored mosaics may also be fabricated by
a colored transparency. Alternately, instead of mosaics, sheet
filters of the desired color are inserted between the light
conducting and the indicia panel or the indicia panel may be
fabricated from a number of different colored plastic sheets, each
of which contain the indicia cut or engraved into each sheet.
As stated hereinbefore, an object of this invention pertains to the
manufacture of illuminable control panels, referred to hereinafter
as edge illuminated panels, particularly a method is provided which
greatly simplifies such manufacture and decreases significantly the
cost of manufacture of such panels and provides a more durable
panel than obtainable heretofore by other known methods,
particularly as they relate to that portion of such panels commonly
referred to as the indicia panel. More particularly, this object
pertains to the use of a photosensitive anodized aluminum or
otherwise imaged anodized aluminum for the production of the
indicia panel of edge illuminated devices.
In the use of microimage transparencies, known generally as
"microfiche" which has gained wide acceptance in mass information
storage retrieval systems, it is well known that such systems
suffer in the case of gelatin-silver halide systems to the extent
that archival storage of such films for long periods of time are
prone to degradation by moisture, excess heat, contaminants in the
surrounding atmosphere, bacteria or mold attack, and a variety of
other problems unless special precautions for the storage and
protection of such films are resorted to. Other systems such as
"Diazo" films may be utilized but generally these systems are in
one way or another inferior to the silver halide-gelatin system. In
addition, such films irrespective of the materials used, on normal
handling during use are subject to scratches, fingerprints, etc.
which in some cases may obliterate the image unless special
precautions are resorted to. Neither of these systems exhibit good
dimensional stability under varying ambient conditions. Therefore,
a specific object of this invention is to provide a highly durable
dimensionally stable microfiche imaging system which is not subject
to any of the above mentioned defects or prone to degradation or
attack in the most severe cases of extreme exposure or
handling.
Use is commonly made of silver halide-gelatin systems for
photomasks which are used as the "negative" for contact printing on
photoresist materials for use in the printed circuit industry, for
example, and as resolution targets on various photosensitive
substrates and a variety of other purposes. In many cases where
extremely high density images are a necessary part of the
photomask, the silver halide-gelatin system will not suffice and
especially where the photomask is subject to rough handling and
physical abuse. Such photomasks are not dimensionally stable under
varying ambient conditions. In such cases evaporated metal films
coated onto a transparent substrate, such as glass or etched
metallic patterns may be resorted to but such articles are
expensive and relatively time consuming to produce and are subject
to generally rather poor resolution capabilities.
It is therefore a further object of this invention to provide a
method for the production of highly durable dimensionally stable
and novel photomasks which are produced efficiently both from a
cost/time standpoint and have high resolution capabilities as well
as a high ratio of density to transmission of light in the
image-nonimage area.
The fourth object of this invention pertains to the use of such
novel highly durable, dimensionally stable, electrically insulating
films, as the basis for the production of printed circuits, in
which not only a higher resolution capability with respect to
conductor width and/or conductor spacings exists compared to that
obtained by conventional "resist" techniques but the substrate
thickness and uniformity as well as surface smoothness is much
easier to control and obtained to a degree higher than that
obtainable by other known methods.
The fifth object of this invention pertains to the use of such
transparent anodized layers containing an overall image which
consists of various dyes and/or silver dye images and/or silver
toned images which may be utilized in the production of color
transparencies which are more durable than that obtainable
heretofore by other known methods for producing such; and by virtue
of this improved durability render such films, particularly
suitable for lighted transparent outdoor information displays.
A sixth object of this invention is a method of increasing the
diffuse transmission density of silver images embedded in an
anodized layer of aluminum by a specific application of metal only
to silver containing portions of the layer by the technique of
"electroless" deposition of various metals, particularly
nickel.
These and other objects will be pointed out or will be apparent
from the description which follows.
As stated hereinbefore the main object of this invention is to
provide a novel method leading to novel products to increase the
utility and broaden the scope of the use of the anodized layer
provided by anodized aluminum both by virtue of the microporous
structure and extreme durability of the anodized layer. For
example, various military and commercial electronic equipment
require that certain graphic information displays be extremely
durable as well as easily fabricated with a view toward the
economic production of such which implies that a low rejection rate
of such articles be achieved or at least that the rejection may be
defined at an early stage of the production, prior to the
investment of considerable material, time and effort in the
fabrication of such devices. With the subject invention it is
possible to achieve all these goals in a variety of methods, the
subject of which forms a part of the various following
embodiments.
In one simplified embodiment of the invention, the indicia panel of
an edge illuminated panel is formed of a fully developed or reduced
silver image embedded within the porous structure of the anodized
layer which forms the opaque, flat black background areas which in
turn outline the indicia which are composed of the anodized layer
which is devoid of reduced silver and hence form the translucent
indicia. In this embodiment a photosensitive anodized aluminum
plate is exposed through and in contact with a suitable negative
which defines in reverse the indicia desired, said latent imaged
photosensitive anodized aluminum plate being subsequently developed
and fixed in the normal photographic mode, laminated face down to a
sheet of light-transmitting glass or plastic and the aluminum metal
backing member removed by etching, resulting in a highly durable
indicia panel-- light transmitting panel combination, the indicia
panel composed of the silver image embedded and sealed within the
anodized structure.
Alternately, suitable sheet filters consisting of various colors or
of a translucent nature may be inserted or laminated between the
anodized indicia layer and a light-transmitting panel.
In another adaptation of this embodiment, the laminating material
may itself consist of white or various colors of a translucent
nature. Alternately, mechanically roughening of the surface of the
light-transmitting panel to enhance the translucent nature of the
overall panel, providing the laminating material is not a solvent
for the light-transmitting panel, may be utilized. In addition,
selected areas of the anodized indicia panel can be mechanically or
chemically removed to provide for the unrestricted passage of
light, uninhibited by either opaque or translucent areas for the
illumination of dials or pointers mounted above the face of the
panel, for example.
In a second embodiment of the invention, in order to provide for a
separation of a small distance between the indicia panel and the
light-transmitting panel use is made of an imaged anodized aluminum
plate which is in this case right reading and which is rigid due to
a heavier gauge and upon which a photographic image of the indicia
is outlined by the developed black silver background. After sealing
the pores of the anodized aluminum by any of the conventional known
methods, a resist material is applied to the reverse surface of the
plate and exposed, for example, through the same negative as used
to photographically contact print the indicia on the obverse and
held in registry thereto. The aluminum backing member is
selectively removed by etching in the nonimage area directly behind
the indicia or translucent portions of the incidia panel and thus
can then be easily mounted at the edge or nontranslucent areas.
Alternately, the indicia portions consisting of the nonsilver
containing anodized layer can be removed and translucent plastic
indicia inserted in the panel.
In another mode the above etched indicia panel may be placed face
down on a flat object and the voids or openings may be filled with
a translucent clear or colored material for example, with the
indicia-bearing anodized layer forming the base of the void or
indicia. In place of the translucent material inserted in the
reverse etched portions, the panel may instead be laminated to a
translucent panel on the reverse anodized aluminum indicia panel or
laminated directly to a light-transmitting panel having on its
surface raised indicia identical to the openings formed in the
above described indicia panel. If a highly specular reflective
backing is required, the reverse of the above indicia panel can
easily be polished after etching. Additionally a thin
light-transmitting metal backing may be applied by evaporation, for
instance.
In another embodiment of the invention metallic conducting strips
for the purpose of providing for the transmission of electrical
current from a source exterior to a panel to a miniature electrical
lamp or lamps, photodiodes or the like, located within the panel
may be easily obtained by a process which is referred to as
"electroless deposition." This process which is described more
fully in a volume entitled "Metal Coating of Plastics" by Dr. E. A.
Lowenheim, * (*Published by: Noyes Data Corporation) can be
utilized to electrolessly deposit various metals such as copper,
nickel, cobalt and the like within and above the pores of the
anodized aluminum layer to form a continuous electrically
conducting path providing the anodized layer is first sensitized
with a metal more noble than the metal to be electrolessly plated
and catalytically able to reduce such anodized aluminum in the
presence of suitable reducing agents. Metallic silver, among other
such noble metals as gold, platinum and palladium, is capable of
catalytically depositing, under the proper conditions, conductor
metals such as copper, nickel, cobalt and the like. Therefore, the
developed silver image can be made conductive either in specific
areas or in the total area containing the catalytic silver image by
simple immersion in the requisite electroless plating solution.
In a further embodiment of the invention, a polychromatic indicia
panel display may be obtained by application of any dye which will
penetrate the pores of the anodized aluminum layer after the silver
image has been developed and fixed, leaving the indicia numerals or
letters translucent e.g. by hand painting, dipping, or in
conjunction with a photoresist. Since the silver image (developed)
is originally at the base of the pores, colored dyes and stains may
be easily applied to the porous translucent nonimage area since the
developed black silver image will effectively mask the dye color if
applied in those areas. After the anodized layer is treated as
above, the plate then is laminated to the light-transmitting panel
face down and the aluminum backing member removed by etching.
The same effect may be accomplished without use of the silver image
by either utilizing a series of colored dyes and/or a black dye,
all of which will be applied by use of a photoresist, offset
printing, silk screening, or any other means known for transferring
an image used by the graphic arts industry.
Alternately, use of a combination of two or more dyes preferably in
particle form may be impregnated in the translucent indicia portion
and laminated face down to the light-transmitting panel and the
aluminum backing removed. By then exposing selected portions of the
indicia to light of a certain color, any word or color in the
indicia panel corresponding to that color will be lighted; whereas
words or colors complimentary to that color will effectively
prohibit light.
Alternately, very thin colored sheet filters which are commercially
available may be applied between the imaged anodized indicia panel
and the light-transmitting panel in preselected areas.
The production of these novel highly durable imaged anodized films
suitable for micro-imaging can be achieved by any of the previously
mentioned techniques described for the production of the edge
illuminated indicia panel. Since the porous structure of the
anodized layer may contain up to 498 .times. 10.sup.9 pores per
square inch, the degree of resolution obtainable, assuming the
silver halide grains reside solely in the individual pores of the
layer as opposed to a surface coating of silver halide, may be of
the order of the film porosity hence the resolution capability may
extend even beyond that required for microfiche into the
ultra-microfiche domain and theoretically even beyond the maximum
resolution capability of visible light. The image may be obtained
by conventional photographic reduction techniques or by direct
contact printing of a negative previously reduced to scale
(microfiche or ultra-microfiche cards). In order to increase the
density of the high resolution anodized image, conventional silver
image intensifiers may be resorted to or alternately, as mentioned
hereinbefore, the silver image may be intensified by the
electroless deposition of nickel, for example, which in the early
stages of such deposition results in a very dense black image
superimposed on the silver within the anodized porous structure.
This process of intensifying such silver images is novel and is
claimed in our copending application Ser. No. 191,635 filed on Oct.
22, 1971 in the United States Patent Office .Iadd.now U.S. Pat. No.
3,822,128 .Iaddend.the disclosure of which is incorporated herein
by reference. By laminating face down the above treated imaged,
anodized aluminum plate with a clear light transmitting binder to a
glass plate or clear plastic substrate and removing the aluminum
backing member, a unique, highly durable microimage is available
which is embedded in the porous anodized structure and which is not
subject to any of the aforementioned defects or prone to attack or
degradation in even the most extreme cases of exposure or handling
compared to conventional microimaging systems.
In another object of this invention, the unique transparent
anodized image may be employed in the production of high
resolution, highly durable novel photomasks which may have a high
density ratio on the image vs nonimage area for the transmission of
light and exhibit excellent dimensional stability under varying
ambient conditions. The same techniques used for the production of
photomasks except the electroless deposition of the metals
deposited on the silver image enclosed in the anodized porous
structure may be continued to the point where a electroless
metallic deposit may actually form a metal bridge over the
pores.
Another object of this invention therefore pertains to the
production of the bridged electrolessly deposited metal pattern
which forms the basis for the production of a novel printed circuit
wherein a suitably conductive metal is electrolessly deposited upon
the embedded silver image to such an extent that the deposited
metal bridges over the silver image in the anodized layer to
provide a continuous electrical path between two or more contacts.
By laminating the resulting plate face down to a supportive
substrate for example, external contact to the enclosed circuit
pattern can easily be made by insertion of any type of conductive
contact pin to achieve electrical continuity between external
contacts and visibly enclosed circuit pattern. Additionally, a
multiplicity of such films may be laminated in a layered structure
thereby providing a high density packing arrangement of electrical
patterns which may be connected to one another by insertion of
contact pins to various depths throughout the multiple layered
arrangement.
In this manner a highly durable enclosed circuit pattern possessing
extremely high resolution capability of conductive paths as well as
extremely thin, smooth substrate films is obtainable.
In a further embodiment, such films may be utilized in conjunction
with the diffusion into such films of certain semiconductor
materials by liquid or evaporation diffusion techniques.
In the practice of this invention, the anodized layer is produced
by anodizing procedures well known in the art. The anodized layer
on the aluminum panel is preferably 15 microns in thickness,
although anodized layers from 1 to 50 microns in thickness have
been used. With thicker anodized layers, for example from 50 to 100
microns thick, sufficient cohesive strength is obtained to the
extent that an additional supporting layer may not be needed.
The adhesive resins or laminates utilized will, of course, vary
depending upon the specific materials to be laminated to the
anodized layer. Among the adhesives which have been effectively
utilized either alone or in various combinations to cohesively bond
to aluminum oxide films but not necessarily limited thereto are
alkyds, vinyls, acrylics and epoxy reins. Epoxy resins are
especially useful in this respect since they may be cured over a
wide temperature range, depending on the curing agent employed and
may be formulated as a single component or two component system and
are amenable to a wide range of colored filler material additions.
Phenolic resins, modified by the addition of various rubbers,
vinyls, or epoxy resins, can also be utilized. Synthetic rubbers
used with phenolic resins are based chiefly on (1) chloroprene to
give neoprene rubber and (2) butadiene plus acrylonitrile to give
nitrile rubber (Buna-N). Vinyl components are typified by the
phenolic-polyvinyl butyral type. Polyethylene resins may also be
utilized. Excellent adhesion can be obtained of aluminum oxide
films to acrylic films or sheets with resorcinol-formaldehyde
adhesives. Polyurethane adhesives may be utilized to bond acrylics
to aluminum, especially when the aluminum surface is first primed
with a polysulfide epoxy. Unsaturated polyester-styrene adhesives
may also be utilized. Among other adhesives used for a variety of
other types of plastic films are included: cellulose nitrate,
alkylcyanoacrylates, furanes, GRS-rubber-based (solvent types),
neoprene-based (solvent types), neoprene-based (water emulsions),
nitrile-rubber-based types (Water emulsion, phenol-formaldehyde
type, polybutadienes silicone resins in various solvents, and
urea-formaldehydes and polyesters. Adhesives that may be utilized
to bond to glass backing members include:
Polyvinyl acetates
Polyvinyl acetates -- dibutylphthalates
Polyvinyl chloride -- acetate alcohols
Polyvinyl butyral -- dibutylphthalates
Methyl methacrylates
N-propyl methacrylates
Polyvinyl alcohols
Polyvinyl chlorides
Cellulose nitrates
Ethyl celluloses
Phenolics
Substituted phenol aldehydes
Aryl sulfonamide formaldehydes
Styrene butadienes
Neoprene Type GN-A
Butadiene acrylonitriles
Epoxies
Various combinations of polymeric substance also useful as glass
adhesives include:
Polyvinyl butyral -- cresylic phenols
Polyvinyl butyral -- oil and ester gum-modified phenolics
Polyvinyl butyral-terpene phenolics
Vinyl copolymers (chloride-acetate-alcohol) vinyl
butyral-phenolis
Polyvinyl chloride-acetate-alcohol with phenolics
Polyvinyl chloride-acetate with phenolics
Phenolic-Buna-N
Phenolic-butadiene-acrylonitriles
Cyclized rubber-polyvinyl chloride acetates
Polyacrylate Buna-N-
Polyamide-epoxies
It is clear that by use of any resin adhesive which will both
effectively bond one component to itself as well as a second
component to itself will generally suffice to effectively bond that
first component to said second component and that where the
situation exists such that a common adhesive cannot be found which
will serve to bond both components to themselves, use may be made
of two separate adhesive layers wherein one component is first
"primed" with a second adhesive which is then compatible to the
primary adhesive. In those cases where an interfacial panel is
inserted between the anodized layer and the light transparent
panel, the same principle may apply in that all three panels may
employ a "primer" coating which may in each case vary depending on
the nature of the panel so that as many as four primer coatings may
be employed for a three panel system and so on if a common
laminating or adhesive material is not available.
The invention will be more fully appreciated from the description
which follows taken in conjunction with the drawings in which:
FIG. 1 is a plan view of a fragment of a transparency; according to
the invention;
FIG. 2 is a view in section taken on plane 2--2 of FIG. 1;
FIG. 3 is a magnified schematic, cross sectional view of a portion
of an unsealed, anodized aluminum plate wherein a fully developed
photographic silver or dye image is embedded;
FIG. 4 is a view of the anodized aluminum article of FIG. 3 which
has been laminated face down to a suitable supporting
substrate;
FIG. 5 is a view similar to FIG. 4 after the aluminum metal backing
member has been removed from said article;
FIG. 6 shows a modification wherein an imaged anodized aluminum
plate is separated by a small air space from a light-transmitting
panel, portions of the aluminum member directly behind the nonimage
portion of the anodized layer having been selectively removed;
FIG. 7 is a similar view showing another embodiment;
FIG. 8 is a view similar to FIG. 5 except that the clear
transparent plastic supporting layer penetrates the pores of the
image-containing, porous anodized layer;
FIG. 9 is a cross sectional schematic view of a further
modification in which the electrically insulating anodized layer
contains a conductive metal pattern superimposed upon a
photographically produced silver image, both of which are embedded
in the pores of the anodized layer;
FIG. 10 is a view similar to that in FIG. 9 but discloses another
embodiment wherein the conductive pattern is formed exterior to the
silver image in the anodized substrate.
FIGS. 11 through 22 are similar to the preceding figures,
illustrating further embodiments of the invention.
Referring, now for purposes of illustration to FIGS. 1 and 2
showing a transparency prepared according to the present invention,
as seen in FIG. 2, the article includes a composite aluminum oxide
layer formed by anodization of a base which has been removed from
the article. The aluminum oxide layer comprises a porous layer 3,
having hills and valleys defining surface pores 6 and underlying
barrier layer 4 consisting of a non-porous aluminum oxide film
originally deposited on the surface of the aluminum base.
Superposed on the anodized layer 3 and secured thereto by a
transparent adhesive 2 is a transparent sheet 1 of glass, quartz,
or clear polymer, such as "Plexiglass," or polymethyl methacrylate.
The walls of some of the pores 6 are lined with silver 7 or other
suitable metal for example as taught in such prior art as U.S. Pat.
Nos. 2,115,339 and 2,766,119. The metal-image-containing pores in
aluminum oxide layer 3 are filled with nickel 5, or other metal
which increases the opacity of a silver image; the nickel or other
metal which being deposited by electroless deposition to an extent
sufficient to fill the pores.
FIG. 3 shows an early stage in the manufacture of the article of
FIGS. 1 and 5. FIG. 3 shows in section a fragment of a porous
anodized aluminum article 10 containing a silver or dye image 15,
produced by known processes such as those described in Mason U.S.
Pat. No. 2,115,339 and in Freedman et al. U.S. Pat. No. 2,766,119.
The image is surrounded by the anodized layer 17 which is both
chemically and physically an integral part of the aluminum base 18
to which layer 17 is connected by a thin non-porous layer 13 of
aluminum oxide commonly called a "barrier" anodic layer in this
art. The opaque area 16 surrounding a non-image, clear or
translucent area 14 may define a set of words or numerals referred
to as indicia.
FIG. 4 shows the imaged anodized plate 10 of FIG. 3, after it has
been suitably bonded face down to a clear light-transmitting panel
20 by means of a clear adhesive 21 to form a further intermediate
in the production of the article of FIGS. 1 and 5.
FIG. 5 shows the article of FIG. 4 after removal of the aluminum
base 18 from the article of FIG. 4. Like the article in FIG. 1, the
resulting article consists of the indicia portion of a light
transparent panel and the supporting clear light-transmitting
panel. It can be seen from FIGS. 2 and 5 that the non-porous
barrier layer surface of the anodized layer now facing the viewer
possesses the same resistance to abrasion and chemical attack and
various other environmental influences as a sealed, anodized layer.
However the panel and the image therein can now be viewed by both
reflected and transmitted light.
By laminating the imaged, anodized aluminum plate shown in FIG. 3
face down to a light-transmitting panel 20 as shown in FIG. 4, and
subsequently removing the aluminum base 18 as shown in FIG. 5, a
method is defined for the production of edge illuminated panels.
For this purpose the light-transmitting panel 20 preferably is
fabricated from an acrylic resin. The adhesive material 21 may
consist of a clear transparent material or may be a white
translucent coating; depending on the degree of contrast both of
reflected and transmitted light that is desired.
FIG. 6 is a sectional view showing a further embodiment of the
invention prepared using a 20 mil thick aluminum plate 18 anodized
on both faces to produce a barrier layer 13 and a porous oxide
layer 17 on each surface. One surface of the article contains a
photographically developed silver or dye image 15. The dye image
forms the black background defining the indicia 14 composed of
non-image areas of anodized aluminum. The reverse side of this
panel is coated with a photoresist material, and then using the
same negative as used for obtaining the silver image 15 on the
other side, and in registry therewith, the resist is exposed to a
U.V. source of approximately 100 millijoules. The resist is cured
in the usual way and unexposed portions are removed. Then the
exposed oxide layer 17, barrier layer 13 and finally the exposed
portions of the aluminum backing member 18 are removed directly
behind the indicia portion of the plate. After portions of layer 18
have been removed and before layer 20 is laminated to the image
bearing anodized aluminum article of FIG. 3, a strip of silicone
resin 25 is affixed to layer 18 and serves to space layer 18 from
clear panel 20 and defines an air space between the two members.
This completes the article of FIG. 6.
FIG. 7 is a fragmentary sectional view similar to the preceding
Figures and illustrates an article formed by assembling the two
image bearing anodized plates together in order to form a circuit
including some source of illumination in the package, in this case
the illumination is furnished by diodes 23.
FIG. 8 illustrates an embodiment in which the anodized layer 17 is
supported solely by the adhesive material 21, which material
preferably penetrates the porous oxide layer 17 to some degree and
forms a thin continuous coherent coating above the porous anodized
structure bearing a metal or dye image 15 which may be modified by
electroless deposition of metal as previously described, prior to
application of layer 21. The layer 21 may comprise a resin which
has been dissolved in a suitable solvent or a liquid plastic
resinous material or wax, or lacquer or the like, or sheet material
which can be colored or clear, translucent or opaque, or any
combination thereof which, when taken together with the above
mentioned anodized layer, constitutes a "free" film and which may
be either rigid or flexible in nature. The opposite face consists
of barrier layer 13 of non-porous aluminum oxide.
FIG. 9 illustrates the result of increasing the electroless
deposition thickness to the extent that the electrolessly deposited
metal completely fills the pores in anodized layer 17 and overflows
the pores. The deposited metal 22 will then deposit outwardly from
the pore, along the anodized surface, until the deposited metal
contacts other electrolessly deposited metal "growing" along the
surface from a neighboring filled pore. In this manner an
electrically conductive bridge 22 is obtained whose path is
determined by the photographically reduced silver image pattern
within the anodized porous layer 17.
FIG. 10 illustrates still another embodiment of this invention
which is similar to that described in FIG. 9 with the exception
that the conductive pattern 22 is exposed and is not enclosed
between the laminating structure 21 and the anodized layer 17.
FIGS. 11 through 22 are similar to the preceding figures,
illustrating further embodiments of the invention.
The examples which follow are intended to illustrate various
aspects of the invention and are not intended to limit the
same.
EXAMPLE 1 (FIGS. 1 and 5)
Utilizing a 3 mil thick, unsealed aluminum plate 6.times.12 inches
using size, the aluminum was anodized in any of the known
procedures, for example those described in the test "The Surface
Treatment and Finishing of Aluminum and its Alloys" by S. Wernick
and R. Pinner, published by R. Draper, Teddington, England (1956
and 1959). Then a silver image was embedded within the anodized
layer, for example in the manner described in U.S. Pat. Nos.
2,115,339 or 2,766,119 or by any other known suitable technique.
The indicia were formed of non-silver areas surrounded by a black
photographic silver background area, the black silver image areas
exhibited a diffuse density of 2.3. The non-silver areas exhibited
a value of 0.1-0.2. The silver-image bearing, unsealed, anodized
plate was laminated face down to a sheet of three-sixteenths inch
thick polymethylmethacrylate using an epoxy adhesive with an amine
catalyst, and subsequently cured at 300.degree.F for 30 minutes.
After cooling the entire panel was briefly immersed in a warm 10
percent sodium hydroxide solution to remove the light oxide
coating; then the entire panel was immersed in concentrated
hydrochloric acid containing 5 percent by volume of 20 percent
hydrogen peroxide solution. The aluminum base was removed in
approximately 1 minute, leaving the article of FIG. 5 which may be
used as an edge illuminated panel laminated to a light-transmitting
panel.
EXAMPLE 2 (FIG. 6)
A 20 mil thick, anodized aluminum plate containing a silver image
embedded within the anodized layer was prepared as described in
Example 1, and then sealed in the usual way. The sealed plate was
coated with a photoresist material and then exposed to an
ultraviolet source of approximately 100 millijoules using the same
negative as employed for the obverse silver image and held in
registry thereto. The resist was then cured by heating at
140.degree.C for 25 seconds after which the unexposed portions of
the resist were removed by immersion in water. The exposed portion
of the anodized layer was bathed in 10 percent sodium hydroxide to
selectively remove the oxide layer, then the exposed aluminum metal
backing member was selectively removed in a hydrochloric acid
etching bath as described in Example 1. The panel was then
laminated at the edge portions of a three-sixteenths inch thick
polymethylmethacrylate panel using a relatively thick bead of a
silicone resin and allowed to cure so that a small air space was
provided between the anodized indicia panel 10 and the
light-transmitting panel 20.
EXAMPLE 3 (FIG. 7)
An unsealed, anodized aluminum plate, the pores of which contained
a silver image in the form of a printed circuit pattern was
electrolessly plated with a commercial electroless nickel solution
which deposited a conductive nickel pattern superimposed on the
silver image pattern. The methyl methacrylate sheet laminated to
the indicia panel prepared as described in Example 1 was drilled
out in a preselected area on the reverse side of the panel to
accomodate gallium phosphide light-emitting diodes which were then
"potted" in place with the leads protruding out of the surface of
the light-transmitting, methyl methacrylate panel of Example 1. An
anodized aluminum plate containing a conductive nickel pattern (See
FIG. 9) was then laminated using a room temperature cure epoxy
adhesive so that each side of the electrically conductive pattern
contacted the appropriate light-emitting diode contact. By masking
the edge portions of the light-transmitting panel in order to seal
them from light, an edge illuminated panel was obtained consisting
of a first continuous circuit completed through the diode to a
second continuous circuit.
EXAMPLE 4 (FIG. 8)
An anodized aluminum foil plate containing a silver image embedded
within the anodized porous structure, prepared as described in
Example 1, was coated with an epoxy resin dissolved in methyl ethyl
ketone. A thin epoxy film was coated on the porous surface and the
epoxy resin penetrated into the porous anodized structure. The
epoxy was cured for 5 minutes at 350.degree.F. The aluminum metal
base was removed as in Example 1. As a result, a "free.sbsp.y film
was obtained which had an image to background density ratio of 2 to
0.1 to diffuse transmitted light. The impregnated anodized portion
of the film would not accept a dye or stain, indicating that the
anodized layer was nonporous.
EXAMPLE 5 (FIG. 11)
An unsealed, anodized aluminum foil plate identical to that
described in Example 1 was uitlized. The imaged plate was immersed
in a dilute aqueous solution of lead acetate, then lightly rinsed,
then immersed in a slightly more concentrated aqueous solution of
ammonium sulfate whereby lead sulfate was deposited as a lining in
the pores of the anodized layer, which was then rinsed thoroughly
under running water and dried. The plate was then laminated face
down to the light-transmitting panel. The supporting aluminum base
was removed. The amount of translucent light passing through the
indicia portion of the indicia panel can be varied depending upon
the amount of white lead sulfate 27 produced in the pores of the
anodized porous structure, which can be determined prior to
laminating the anodized plate to the light-transmitting panel.
Since the black silver image 15 is present prior to the lead
sulfate precipitation, the diffuse density of the silver background
image portion is increased from 2.5 to 3.5.
EXAMPLE 6 (FIG. 12)
An unsealed, anodized aluminum foil plate having the approximate
rectangular dimensions of 6 .times. 12 inches and 3 mils thickness,
and containing an image defining indicia as described in Example 5,
but, in addition, having areas 12 devoid of any material, defining
openings for the unobstructed passage of light from the
light-transmitting panel was utilized. A double faced polyester
adhesive film 20' was positioned over the image, the adhesive film
having an opening 12 corresponding to and superimposed over each of
the desired openings 12 defined in the anodized layer and then heat
laminated face down to a clear allyldiglycolcarbonate sheet 20
three-sixteenths inch thick and having the same approximate
rectangular dimensions as the imaged anodized plate 10. The
aluminum metal base 18 was then removed and the area defining that
portion of the anodized layer containing no adhesive was removed by
probing under and lifting out the sharply defined, non-bonded
section 12 which now allows for the unobstructed passage of light
from the light-transmitting panel for the purpose of illuminating
dials and pointers and the like situated above the edge illuminated
panel.
EXAMPLE 7 (FIG. 9)
A 3 mil thick, anodized aluminum foil plate which contained a
photographic silver image embedded in the unsealed, anodized layer
in the form of a conductive pattern or printed circuit was immersed
in an electroless nickel plating solution until a conductive
pattern of nickel was deposited on the photographic silver image.
The plate was then laminated face down to a thin methyl
methacrylate sheet using a phenolic-epoxy adhesive. The aluminum
base was then removed by the technique described in Example 1.
EXAMPLE 8 (FIG. 10)
An unsealed, anodized aluminum foil plate approximately 0.003 inch
thick upon which an anodized layer approximately one-third of a mil
in thickness is present on one side only of the foil plate and
which contains a reduced silver image defining a printed circuit
was coated and impregnated with a dilute epoxy resin (Shell's Epon
1004) dissolved in methyl ethyl ketone. Upon drying, the film was
cured by heating at 350.degree.F for 5 minutes after which the
entire exposed aluminum metal backing member was removed by etching
in a saturated solution of mercuric chloride and rinsed. The
barrier oxide layer 13 (see FIG. 5) was then removed by a brief
immersion in an aqueous solution containing 35 milliliters of
phosphoric acid per liter and 20 grams of chromic acid per liter at
room temperature. The plate was then rinsed thoroughly in running
water. The reduced silver image was now exposed, being held in
place within the epoxy impregnated anodized cell walls. The panel
was then immersed in an electroless nickel plating bath which
resulted in deposition of a conductive pattern of nickel
superimposed on the silver image.
EXAMPLE 9 (FIG. 5)
A sealed, anodized aluminum foil plate containing a reduced silver
image which had been intensified by a chemical deposition technique
using a conventional photographic gold intensifier-toner solution
was laminated face down to a sheet of optically clear transparent
glass using a clear, heat curing epoxy resin-catalyst adhesive
formulation. The aluminum metal backing member was then removed as
described in Example 1. The above described panel was found to be
equivalent to a normally sealed, anodized layer, exhibiting
outstanding chemical and durability characteristics and would not
accept a dye or stain.
EXAMPLE 10 (FIG. 13)
An unsealed, anodized aluminum plate similar in respect to Example
1 was utilized except that the laminating adhesive 21' was composed
of a white translucent epoxy-phenolic combination resin to laminate
the indicia panel to the light-transmitting panel. The
light-transmitting panel exhibited an increase in the transmitted
diffuse lighting effect in the translucent areas forming the
indicia when the panel was edge illuminated by a miniature tungsten
filament bulb enclosed in a red transparent filter cap and the
sides and back portion of the light-transmitting panel was sealed
with respect to light by laminating a highly reflective aluminum
foil which a pressure sensitive polyester adhesive.
Colored sheet filters may be laminated between the
light-transmitting panel and the anodized layer or the laminating
material itself may be of a translucent color rather than white or
clear.
EXAMPLE 11 (FIG. 14)
An image bearing, unsealed, anodized aluminum plate was again
utilized except a thin sheet of red colored polyvinyl chloride 20'
was laminated to the anodized surface and to the methyl
methacrylate panel using an unsaturated polyester-styrene adhesive.
The entire package was then treated as in Example 1 to remove the
aluminum metal backing member.
Since certain portions of the indicia panel must allow internally
transmitted light to pass through the indicia panel unobstructed by
either the opaque area 16 or the translucent area defined by 14 for
the purpose of illuminating dials, pointers, or other indicators
located above the indicia panel, the imaged anodized aluminum plate
may be made discontinuous in those areas by simply drilling or
routing out, for example, in those areas 12 prior to lamination of
the light-transmitting panel.
EXAMPLE 12 (FIG. 15)
A sealed, imaged, anodized aluminum plate was prepared as described
in Example 2 except that the selectively removed portions of the
aluminum metal backing layer were filled with a white translucent
epoxy formulation 26 using the obverse anodized layer as the
supporting member to form the indicia. Those areas predetermined
for the unobstructed illumination of light for the purpose of
illuminating dials and pointers located above the panel were left
unfilled and the fragile unsupported anodized layer mechanically
removed in those areas.
EXAMPLE 13 (FIG. 16)
A sealed, anodized aluminum plate 0.020 inch thick and of
rectangular dimensions approximately 6 .times. 12 inches was
prepared wherein within the sealed, anodized layer was a black dye
blanket color, and the fragile unsupported anodized portions from
which the aluminum backing member had been selectively removed were
themselves removed by the method described in Example 12 and
preformed white plastic translucent inserts 26 were placed into
those areas defining the indicia, whereas those areas defining
portions to allow for the unobstructed passage of light in order to
illuminate dials and pointers located above the panel were left
unfilled.
Instead, the indicia portions of the panel where the aluminum
backing member has been selectively removed may be filled from the
reverse side with a translucent material using the anodized obverse
layer as the supporting member for the filled portion. Alternately,
the anodized layer forming the indicia portion of the panel may
easily be removed by either a mechanical or chemical etching action
and the total void filled with a preformed plastic translucent
insert. This provides for the unobstructed passage of internally
transmitted light for the purpose of illuminating indicators and
the like situated above the indicia panel. Or, the above described
panel after the selective removal of the aluminum metal backing may
be laminated directly to a translucent glass or plastic insert
which, as in previous examples, may then be laminated directly to
the light-transmitting panel or supported above the
light-transmitting panel and separated by a small air space. The
above described panel may be mounted to the previously mentioned
translucent panel insert or directly to the light-transmitting
panel upon which contains raised or embossed indicia identical with
an in juxtaposition to openings formed in the above described
indicia panel.
EXAMPLE 14
Two imaged, anodized plates were made transparent in selected areas
as described in Example 2, except that a white translucent
polyvinyl chloride panel was laminated directly to the reverse side
of the anodized aluminum plate using an unsaturated
polyester-styrene adhesive. One such plate was mounted above and
separated from the methylmethacrylate panel by a thin silicone
resin bead placed around the periphery of the panel. The second
plate was laminated directly to the methylmethacrylate panel using
the unsaturated polyester-styrene adhesive.
EXAMPLE 15 (FIG. 17)
A sealed, imaged, anodized aluminum plate was made transparent in
preselected areas as described in Example 2, and a thin white
translucent polyester film was set on the reverse side of the
anodized plate and heated until the polyester became soft and
sagged into and through the preselected openings of the anodized
aluminum plate, thereby forming raised indicia identical with an in
juxtaposition to the openings formed in the above described panel,
thereby serving to accentuate the indicia. The above described
panel arrangement was then adhesively bonded using a room
temperature core epoxy and mounted above but not in contact with a
three-sixteenths inch thick methylmethacrylate panel using a thin
bead of silicone resin around the periphery of the panel and
allowing to cure at room temperature.
EXAMPLE 16
A sealed, imaged, anodized aluminum plate was made transparent in
preselected areas as described in Example 2 and subsequently
treated as described in Example 15, except that the double panel
arrangement containing raised translucent indicia was laminated
directly to the methyl methacrylate panel using a two-sided heat
laminated polyester adhesive film coated onto a Mylar base.
In still another mode, the above described indicia panel provides
for the option of utilizing a highly specularly reflective surface
since the above described reverse side of the indicia panel may be
polished either before or after the selective removal of the
aluminum metal backing member.
EXAMPLE 17
A sealed, imaged, anodized aluminum plate 0.020 inch in thickness
was made transparent in preselected areas as described in Example 2
and subsequently treated as in Example 12, except that the reverse
side of the aluminum panel was mechanically polished after removal
of the oxide layer by buffing on a wheel in contact with a
commercial polishing rouge, followed by a light buffing using a mop
consisting of a series of calico discs sewn together near the
center of the wheel. The aluminum was then brought to a mirror
finish using a soft muslin disc and Vienna lime, and then laminated
to an allyl glycolate panel having smooth parallel, polished
surfaces using a heat curable polyester adhesive to effect the
lamination.
The anodized aluminum metal article may be used in the unsensitized
state, i.e. the preformed panel after removing the aluminum backing
member in preselected areas together with the anodized layer
directly above said area may then be colored by a dye or other
suitable coloring material and then sealed in the conventional
mode, irrespective of whether the anodized plate has been first
laminated to a translucent panel or a light-transmitting panel
either in optical contact or by maintaining a small separation of
the anodized aluminum-translucent panel combination from the
light-transmitting panel or by utilizing the specularly reflective
backing concept.
EXAMPLE 18
An unsealed, unsensitized, anodized aluminum plate, 20 mils in
thickness and approximating a rectangular shape of 6 inches by 9
inches in size, both sides of the plate having an anodized layer of
about 0.5 mils thickness was laminated to a three-sixteenths inch
thick polymethyl methacrylate panel of the same dimension using a
heat curable two-sided translucent polyester adhesive. The
laminated panel arrangement was then coated with a photoresist and
exposed to a negative wherein the indicia pattern was not light
struck whereas the resist area conforming to the background area
was exposed, causing these areas to become insoluble to water,
mineral acids and alkali solutions using an ultraviolet light
source of approximately 100 millijoules exposure. Following
exposure, the resist coating was cured by heating at 150.degree.F
for 1 minute then immersed briefly in water to remove the unexposed
portions of the resist forming the indicia. Since this resist
material forms a color in the light struck area, the quality of the
finished product can be evaluated at this point. The exposed
portions of the anodized layer were then removed by a brief
immersion in an aqueous 10 percent potassium hydroxide solution at
50.degree.C. The exposed aluminum metal was then removed in a
concentrated solution of hydrochloric acid containing 5 percent by
volume 30 percent hydrogen peroxide and rinsed and dried, leaving
the second anodized layer intact which now forms the translucent
indicia. The plate was then instantly dyed black using a commercial
black aluminum dye. The anodized layer was not sealed by immersing
in a cobalt nickel acetate bath for 5 minutes at 95.degree.C. Since
the barrier layer constituting the translucent indicia facing the
viewer represents a sealed or nonporous anodized structure, this
portion of the panel will not accept a dye. For the purpose of
permitting the unobstructed passage of light from the
light-transmitting panel for the production of illuminating dials
and pointers located above the face of the panel, those portions
constituting such areas were removed by dissolving the second or
interfacial anodized layer by the alkaline treatment. Since the
indicia are now situated on a plane below the obverse surface of
the plane of the indicia panel, this serves to further accentuate
the contrast between the translucent indicia and the black opaque
background of the indicia panel when viewed by reflected light. In
addition, by removing the interfacial laminated anodized portions
of the indicia panel, the degree of internally transmitted light
can be varied from 100% transmission to any lesser degree of
diffuse transmitted light by filling the exposed indicia portions
with a suitable translucent material, hence a high degree of
diffuse light control is now attainable.
EXAMPLE 19
In this example the exact same procedure was followed as described
in Example 18, except the anodized aluminum utilized was anodized
on one side only, the interfacial layer or side being of a high
specular reflectance which was placed in optical contact with the
light-transmitting panel using a clear, two-sided, heat laminated,
polyester resin film. In this case it was necessary to make the
indicia translucent which was accomplished by filling the indicia
portions of the panel with a white translucent polyester resin.
EXAMPLE 20
An unsealed, unsensitized, anodized aluminum plate having the
rectangular dimensions of 8 inches by 11 inches, 20 mils in
thickness, being covered uniformly on both sides by an anodized
layer approximately 0.005 inch in thickness was first immersed in a
dilute aqueous solution of lead acetate, rinsed lightly, then
immersed in a slightly more concentrated solution of ammonium
sulfate after which the plate was rinsed thoroughly with water and
dried, which serves to precipitate white lead sulfate within the
porous anodized structure. The plate was then coated on both sides
with the same resist material described in Example 18 and the
obverse side exposed in the same manner; however, the reverse side
was exposed using a direct positive transparency with respect to
the transparency used for the obverse resist exposure and held in
registry thereto and constructed such that the light protected
areas constituting the indicia image of the positive transparency
were somewhat enlarged with respect to the indicia of the obverse
portion of the panel. Following exposure of both sides of the
panel, the resist was fully developed and cured as described in
Example 18, and the exposed portions of the anodized layers on both
sides removed by immersion in an aqueous 10 percent potassium
hydroxide solution which was heated at 60.degree.C. then rinsed
thoroughly in water and dried. The obverse side of the panel now
contains exposed aluminum metal which forms the indicia and those
areas provided for the unobstructed passage of light which is
surrounded by the anodized layer containing lead sulfate. The
reverse side of the panel contains the lead sulfate bearing
anodized layer in the form of enlarged indicia directly behind the
exposed aluminum forming indicia but the anodized layer is removed
behind the areas which are to provide for the unobstructed passage
of internal transmitted light for the illumination of dials and
pointers which will be subsequently located above the indicia
panel. The exposed aluminum reverse surface after removal of the
anodized layer now contains a highly specular reflective surface
which was laminated in optical contact using a heat curable
polyester adhesive to a polymeric allyl glycolate transparent
panel, three-sixteenths inch thick, and having the same rectangular
dimensions as the anodized panel and having its upper and lower
surfaces in parallel relation to each other and polished to provide
a smooth optical surface. The laminated panel was then immersed in
a bath of concentrated hydrochloric acid containing 5 percent by
volume of 30 percent hydrogen peroxide which served to remove the
exposed aluminum metal forming the indicia of the obverse portion
of the indicia panel, leaving the interfacial anodized layer
containing white lead sulfate intact. The indicia panel was then
instantly colored using a commercial black dye and sealed by
immersion in a cobalt-nickel acetate bath for 5 minutes at a
temperature of 95.degree.C. Since the interfacial laminated
anodized layer representing the indicia and facing the viewer
constitutes an intact barrier layer, these areas will not accept a
dye and will remain white or whatever color was initially chosen.
The areas which are to provide unrestricted transmitted light from
the light transmitting panel now consist of the clear polyester
laminating surface and also will not accept a dye, providing the
dye vehicle is not a solvent for the laminating agent.
EXAMPLE 21 (FIG. 5)
An unsealed, imaged, anodized foil plate having a brushed or matte
finish was utilized as described in Example 1, except the plate was
laminated face down to a pressure sensitive, heat sensitive, clear,
polyester film supported on a polyester backing member. The entire
aluminum metal backing member was then removed and the resulting
film was found to be translucent in the nonimage areas.
EXAMPLE 22 (FIG. 5)
A sealed, imaged, anodized aluminum foil plate was treated exactly
the same as described for Example 21. In this case a more
transparent clear, nonimage area was evident than that defined in
Example 21 since the anodized layer was no longer porous but
amorphous and therefore would not scatter transmitted light to the
same degree.
Such films may be used for a variety of purposes, depending upon
the nature of the material 21. When the supporting material 21
constitutes a clear or translucent coating, the film so produced
may be used as previously described for the production of the
indicia panel of edge illuminated panels. Additionally, in this
respect the supporting material 21, if of sufficient thickness and
optical clarity, may constitute the light-transmitting panel 20
itself referred to in FIG. 5.
By utilizing very thin films which are optically clear and
transparent such as layer 21 of FIG. 8, methods are thereby
available for the manufacture of various articles such as
photomasks, microimaging cards and holograms, for example, and
which form additional objects and embodiments of this invention and
which will now be described more fully.
It is well known to those familiar in the art of providing porous
anodic oxide coatings of various aluminum articles that the
porosity of various oxide coatings produced may routinely vary, the
number of pores ranging between 25 .times. 10.sup.9 and 500 .times.
10.sup.9 pores per square inch, depending upon the electrolyte
utilized in the anodizing bath, the voltage employed and various
other factors. Assuming that a photographically sensitized anodized
aluminum article containing silver halide embedded within such a
porous structure to the extent that the sensitive material resides
solely within the porous structure as opposed to coating the anodic
oxide surface, then such an article when exposed to light and
developed and fixed in the normal photographic mode would represent
a resolution capability of the same order of magnitude as that of
visible light itself. However, due to various factors such as
internal reflections and the scattering of the impinging light
rays, as well as the possibility of the existence of a mixture of
macroporous and microporous structure as well as the possibility of
discontinuities and nonlinearity of the individual pores
themselves, this theoretical resolution capability of
photographically sensitized anodized aluminum articles is not
realized in practice. However, line pairs of the order of 1,200 to
1,600 lines per millimeter are routinely realized with routinely
produced anodic layers which is well within the resolution range
required for the production of reflectance type microimaging
articles. By utilizing the technique of removing the aluminum metal
backing member referred to previously, the article then described
in FIG. 8 forms the basis for the production of novel highly
durable transparent microcards which may be produced by
conventional photographic reduction techniques or by contact
printing of conventionally reduced negatives, referred to commonly
as "microfiche" cards. The photographic silver image thus produced
may be enhanced by any of the well known techniques referred to as
"image intensification" prior to applying layer 21, e.g. as
described in the following Examples.
EXAMPLE 23
A sealed, anodized aluminum foil plate was contact printed using a
conventional silver emulsion reduced negative or microfiche card as
the negative in such a manner to make the anodized image right
reading. The silver image produced in the anodized layer was then
toned with a conventional gold toning solution in order to increase
the density of the image portion of the anodized aluminum which was
then sealed and heat laminated to an epoxy coated polyester sheet 3
mil in thickness and the entire aluminum backing member removed.
When viewed with magnified transmitted light, equivalent resolution
capability to that of the original was evident, except the image
was now reversed.
EXAMPLE 24
A reduced image was obtained identical to that described in Example
23, except the anodized layer was removed after removal of the
aluminum metal backing member by immersing the film in a 10 percent
sodium hydroxide solution for several minutes at room temperature.
The resulting film when viewed under magnified transmitted light
was characterized by a higher degree of light transmission in the
nonimage area of the plate than that obtained in Example 23. Since
the films described in this example and in Example 23 are now
positive transparencies of the original microfiche card, a product
which is not only ideally suited for archival storage but also
suited for the reproduction of contact prints therefrom is
obtained.
Alternatively, the density of the reduced silver image may be
increased by a technique referred to as "electroless metal plating"
and which briefly consists of catalytically depositing a metal less
noble than that of silver upon the reduced silver image in the
presence of suitable reducing agents; the silver image in this case
acting as the catalytic nuclei upon which the reduced metal is then
deposited. In this manner a metal such as nickel, for example, may
be deposited upon the reduced silver image within the anodized pore
itself which results in an extremely black image, as illustrated in
Example 25.
EXAMPLE 25 (FIG. 18)
An anodized aluminum foil plate was utilized and treated exactly as
in Example 24, except the photographic silver image was intensified
by an electroless nickel plating solution to a dense black image
having a diffuse transmitted light density ratio of 3 to 0.1 in the
image-nonimage areas.
The article produced was found to be very durable, possessed a high
density ratio of transmitted light regarding the ratio of density
in the image area compared to the non-image area, exhibited high
resolution capabilities and was extremely well suited for use as a
permanent microimage record or for use as a photomask.
EXAMPLE 26 (FIG. 9)
An anodized aluminum foil plate was obtained as defined in Example
23, except the electroless nickel deposit was increased to the
point that the image was of a reflective metallic appearance and
electrical continuity was obtained between connecting lines.
The product of FIG. 9, therefore, provides not only for the extreme
density of the image equivalent to metal photomask but increases
also the simplicity of producing such masks as well as the
resolution capability of such masks irrespective of the electroless
metal deposition utilized.
EXAMPLE 27 (FIG. 19)
A silver imaged, anodized foil plate 0.003 inch thick containing an
anodized layer approximately 10 microns thick containing line pairs
one-half inch in length and consisting each of 5 microns
separations and 5 microns wide; 10 micron separation and 10 micron
wide, up to and including in the same manner 20, 50 and 100 micron
lines, was obtained and immersed in a commercial electroless nickel
plating bath until a metallic nickel deposit was obtained
superimposed above the silver image and extending above the
anodized surface pores. The foil plate was laminated face down to a
clear, heat curable, polyester adhesive supported by a 0.03 inch
thick polyester film and the aluminum metal backing removed by
etching in concentrated hydrochloric acid. The anodized aluminum
backing member was then removed in 10 percent aqueous sodium
hydroxide solution, leaving the silver-nickel image intact and
laminated to the polyester film. This resulted in a clear
transparent background photomask wherein the diffuse light
transmission density ratio was 4 to less than 0.1 in the
image-nonimage area containing line widths and separations of 5,
10, 20, 50 and 100 microns.
Among those metals which can be electrolessly deposited on the
developed silver image or a suitable sensitized silver image
enveloped within the high dielectric, electrically resistant
anodized layer as described in an application filed on Oct. 22,
1971, Ser. No. 191,635, and which are useful for various electronic
applications including printed circuits and the like are: silver,
copper, nickel, iron, chromium, cobalt, gold, platinum, and
palladium, including also certain alloys or mixtures of metals such
as nickel-cobalt, cobalt-phosphorus, nickel-iron, etc. which are
also useful in some applications for the unique magnetic properties
which find use in obtaining the recording and reproduction of
information. This is achieved by utilizing the previously mentioned
photographically developed silver image embedded in the anodic
porous structure as before wherein the porous structure is sealed
and the resulting plate then coated with the supportive film 21 and
an etchant used to remove the aluminum backing member which has a
solvent effect on the anodized layer as well but does not attack
the developed silver image which is subsequently used to
catalytically deposit the various electrolessly deposited metals
referred to previously. The solvent so chosen can be selected to
satisfy any one of three conditions; (1) solvent for the aluminum
backing member only, (2) solvent for the aluminum backing member
plus a slight solvent action on the anodized layer and which can be
confined to attack on primarily the barrier layer, or (3) solvent
attack on both the aluminum backing member and the anodized layer
to the extent that the anodized layer surrounding the silver image
is removed, thereby necessitating in this case that the supportive
layer 21 contact the silver image and that the anodized aluminum
layer in this case is not sealed. This, of course, results in a
substrate composed of a plastic film only, which has now been
selectively sensitized for the electroless deposition of various
metals referred to earlier. This aspect of the invention is
described in the following examples:
EXAMPLE 28
An unsealed imaged anodized aluminum foil plate which had been
polished to be specially reflective was provided with a silver
image defining a conductive pattern or printed circuit arrangement
upon which an electroless deposition of nickel metal was deposited
as in Example 3, was laminated face down to a pressure
sensitive-heat sensitive polyester film coated onto a polyester
substrate and the entire aluminum backing member was removed as
described in Example 1. Electrical contact was made to the enclosed
circuit pattern by insertion of contact pins to contact points
within the anodized structure. The dielectric strength constant of
the unsealed anodized layer was approximately 7.5 and the surface
smoothness, limited by the polishing lines of the original aluminum
metal and replicated by the anodized layer was approximately 1-3
microinches CLA (Center Line Average).
EXAMPLE 29
An, unsealed, anodized silver imaged foil plate was utilized
wherein the silver image was defined exactly as described in
Example 28 and which was laminated face down to an optically flat
glass substrate using a two part epoxy resin adhesive which was
heat cured at 350.degree.F for 30 minutes after which the aluminum
metal backing member was removed by etching as described in Example
1. Next the anodized barrier layer only was removed by immersing
the panel in an aqueous solution of phosphoric acid (3.5 percent by
volume) and chromic acid (2 percent weight per volume) at room
temperature for 1 minute and thoroughly rinsed which served to
expose the silver image within the anodized epoxy layer.
The resulting panel was then immersed in a commercial electroless
nickel plating bath whereupon an electrically conductive nickel
deposit was obtained superimposed on the reduced silver image and
was primarily above the anodized surface as described in FIG. 10.
The epoxy-anodized layer was now characterized by a surface
smoothness of approximately 0.5 to 1 microinches CLA.
EXAMPLE 30 (FIG. 10)
An unsealed imaged anodized foil plate was laminated to a glass
plate using an epoxy adhesive as described in Example 29 after the
reduced silver image had been first toned with a commercial gold
toning solution. The resulting panel was then etched as before to
remove the supporting aluminum backing member then the entire
anodized layer was removed using an aqueous 10 percent sodium
hydroxide solution resulting in the silver-gold image now being
supported entirely by the epoxy resin. The panel was then immersed
in a commercial electroless nickel plating solution and a
conductive pattern of nickel was superimposed on the silver-gold
image.
EXAMPLE 31
A panel was prepared the same as defined in Example 30 wherein the
laminated anodized layer was removed and the glass-plastic plate
was immersed in an electroless nickel solution whereupon an
electroless deposit of nickel was superimposed on the silver image
defined on and in contact with the epoxy resin.
Inasmuch as the nature of the solvent attack on the aluminum
backing member and/or the anodized layer can be varied, it is
possible to provide control over the various degrees of surface
smoothness desired.
Referring now to FIG. 7, the invention is shown applied to a
portion of a finished product of an edge illuminated panel which
provides a unique method for transmitting electric current outside
the light-transmitting panel 20 to the illuminating source 23
generally located within the light-transmitting panel and which may
comprise miniature tungsten lamps or light-emitting diodes or the
like. Those areas in FIG. 7 designated as 30 and 31 constitute
electrolessly deposited metallic-conducting strips obtained as
described in FIG. 9 from which conductor 30 may be made
discontinuous from 31. Assuming that conductors 30 and 31 are
connected to a source of external electrical energy, current flows
from conductor 31 through illuminating source 23 through conductor
30 back to the external source. This is described in Example
32.
EXAMPLE 32 (FIG. 20)
An unsealed, anodized (one side only) aluminum foil panel 0.003
inches in thickness and having overall rectangular dimension of 12
1/2 in. .times. 23 1/2 in. containing a developed silver image
wherein a series of 8 various dials were arranged, the indicia and
other markings as before comprising the non-image portions anodized
layer and containing thereupon a white barium sulfate 27 depost was
prepared with variously arranged cut-out portion of the panel for
dial illumination. A second panel containing a conductive pattern
of electroless deposited nickel was superimposed upon the developed
silver image in such a manner to provide electrical current in
parallel to a series of red gallium phosphide light emitting diodes
arranged in such a manner that all portion of the instrument panel
would be illuminated in case of failure in any one adjacent light
source. The diodes were then soldered into place using a commercial
lead base solder and suitable connector pins inserted thru the
panel and soldered into place to provide a continuous path for the
flow of current when connected to a suitable external source. The
panel was then instantly dyed using a commercial black aluminum
dye, then a white barium sulfate precipitate applied in the pores
above the black dye. A three-sixteenths inch thick rectangular
methyl methacrylate panel 12 in. .times. 23 in. having suitable
arranged openings to accommodate the various lamps and connectors
and dial openings was coated with a clear two part epoxy
room-temperature cured resin formulation and the light emitting
diode panel assembled to one side of the light transmitting panel.
The indicia bearing panel was then assembled to the opposite side
of the light transmitting using a clear heat curable double faced
polyester laminating adhesive on a polyester substrate containing
suitable arranged opening corresponding to those portions utilized
for the illumination of dials or pointers arranged above the
instrument panel and the edges folded down over the edge portion
and heat laminated also to the light emitting panel. The connector
pins extending through the reverse side of the edge illuminated
panel were masked off with an adhesive tape and the entire panel
immersed in a saturated solution of mercuric chloride to remove the
entire aluminum backing layer surrounding the light transmitting
panel.
Alternately the construction illustrated in FIG. 10 may be utilized
wherein the illuminating source 23 utilizing external electrical
connectors would extend through the anodized layer to provide ready
access for purposes of replacement in the event of failure of any
such illuminating source.
EXAMPLE 33
An anodized unsealed aluminum foil panel 0.003 inches thick and 12
1/2 inches .times. 23 1/2 inches in rectangular shape and
containing the developed silver image outlining the non-image
anodized areas which formed the same pattern as described in
Example 32 was prepared in this example however omitting the
impregnated white coating. A second panel was prepared again
containing an electrolessly deposited conductive nickel pattern
superimposed on the silver image, also as described in Example 32,
and containing a white lead sulfate precipitate impregnated in the
anodized porous layer surrounding the conductive pattern. A
three-sixteenths inch thick light transmitting panel, 12 inches by
23 inches and having the same shape as the two aluminum oxide
panels, consisting of a polished optically smooth methyl
methacrylate panel having its two sides in parallel relation to
each other was coated with a white translucent polyester double
faced adhesive which in turn was coated onto a polyester supporting
film. Both anodized aluminum panels were then heat laminated to the
light transmitting panel with the indicia panel being folded down
over the edge portions of the methacrylate panel. The entire panel
was then immersed in a concentrated hydrochloric acid bath
containing 3 percent by volume of 30 percent hydrogen peroxide to
remove the entire aluminum metal backing member. The conductive
pattern is now easily visible on the reverse side of the panel as
well as the portions allocated for the placement of the
illuminating sources. The illuminating positions were then routed
out exactly to the size of the miniature tungsten light sources
plus the red filter caps enclosing each source and were inserted
into the sockets and the pins of each lamp soldered into place
using a commercial lead base solder after the anodized area
immediately above the contact points was exposed by swabbing the
area with 10 percent sodium hydroxide solution. The entire base
area including the solder joints was then coated with a silicone
adhesive-elastomer. This elastomer had a peel strength of 5 lbs.
which is sufficient to bond the lamp area yet can be removed
without destroying the integrity of the panel, and yet provides
access to each lamp and solder joint which facilitates access to
each lamp for purposes of replacement.
It is evident that the same techniques may be employed using the
obverse portion of the panel utilized as the indicia panel or that
a combination of the two panels may be utilized so that the indicia
panel may carry electrical current to one side of the illuminating
source 23 and return through the conductive layer defined on the
reverse side of the panel back to the external source.
EXAMPLE 34
An indicia panel identical to that described in Example 33 was
prepared except a conductive electroless nickel deposit was
obtained over the entire silver image background area surrounding
the non-image pattern containing impregnated barium sulfate
corresponding to the indicia and other openings marking those areas
for the illumination of dials and pointer located above the final
panel. The reverse panel was prepared in the same manner being a
mirror image of the above described indicia panel except that the
indicia were somewhat enlarged. This panel was also made conductive
by the electroless deposition of nickel throughout the silver image
area and again the imaged portions were impregnated with white
barium sulfate. As with the indicia panel the barium sulfate
precipitation is specific in the indicia area since the surrounding
metallic nickel area is non-porous.
A three-sixteenths inch thick panel of clear, light transmitting
polymethylmethacrylate identical to that described in Example 32
was utilized, and was provided with polished cylindrical bores
extending completely thru the light transmitting panel in order to
accommodate a series of gallium phosphide red light emitting diodes
containing thin flat wire leads. The openings in the panel were
arranged in order to provide illumination evenly throughout the
panel and to provide overall illumination in the event of failure
of an adjacent diode. The openings were of a size to permit a
friction fit of the cylindrical diode and one lead which were
inserted into the panel with the lead facing the opposite direction
of the main direction of illumination desired. Both leads of each
diode were extending above and below the plane surfaces of the
light transmitting panel and a double faced, clear, polyester
laminating adhesive supported by an interfacial polyester film was
placed in contact on both sides of the panel with the leads of the
light emitting diodes protruding thru the laminating film which
also was discontinuous in those areas which were to be illuminated
directly by internally transmitted light. The thin flat diode leads
were then bent at right angles, parallel to the plane of the plane
of the light transmitting panel and in contact with the adhesive
laminating film.
Both the electroless nickel plated obverse and reverse panels
containing indicia were then heat laminated to the polyester
adhesive-methyl methacrylate panel with the flat diode leads
contacting the nickel plated area of each panel thereby providing
electrical continuity from the indicia panel, thru the diode and
back through the reverse panel. The folded over edge portions of
the panel were separated by excess laminating film to prevent
shorting through the circuit. Then entire panel was then immersed
in a saturated solution of mercuric chloride to remove the aluminum
metal backing member after which external contacts were made thru
the panel by inserting a contact pin through the reverse side of
the panel to contact the obverse nickel plated area surrounded by a
cylindrical socket arrangement to contact the reverse nickel plated
panel and both contacts were then potted in place using a room
temperature cure, two part epoxy adhesive.
EXAMPLE 35
A sensitized anodized aluminum plate 0.02 inches in thickness and
approximately three inches by six inches of rectangular dimensions
containing on one side a left reading, enlarged indicia pattern
composed of nonimage anodized areas surrounded by a conductive
electroless nickel background area superimposed on the silver image
and containing in registry thereto and therefore right reading, on
the reverse side a sealed silver image embedded within the anodized
porous structure surrounding etched indicia which had been filled
with a white translucent epoxy formulation using the anodized layer
on the reverse side of the panel as the supporting layer. A second
panel of sensitized anodized aluminum of the above same dimensions
was prepared wherein the indicia were again of enlarged or
exaggerated dimensions composed of non-image anodized aluminum
which were surrounded by electrolessly deposited conductive nickel
superimposed on the silver image. The indicia were in this case
right reading.
A clear polymethyl methacrylate panel three-sixteenths inches thick
and having the same overall dimensions as the above described
panels, and having both smooth polished surfaces in parallel with
each other was bored out near each corner and red light emitting
gallium phosphide diodes containing a double pin connector
arrangement were inserted in the panel with one lead extending
through to the top surface and the other through to the reverse
surface. Each contact lead was then furnished with a conductive
epoxy resin bead which could be cured at room temperature. The
indicia or top panel were then set into place using a thin bead of
a room temperature cure silicone resin placed around the periphery
of the indicia panel to provide a small separation and which served
to contact the uncured conductive resin bead coating with the
electrolessly deposited nickel surface. The reverse panel was then
optically bonded to the methacrylate panel using a clear room
temperature cure epoxy resin again with the conductive resin
contacting the conductive nickel surface and allowing the entire
single package arrangement to cure at room temperature.
The edge portions of the panel were covered by a pressure sensitive
double faced polyester adhesive tape containing a high reflectivity
aluminum foil which was separated from the indicia panel and the
reverse panel by the adhesive.
Referring now again to FIG. 8, by utilizing an anodized aluminum
plate which may or may not contain (at the discretion of the user)
a photographic silver image which in turn may or may not be toned
to a color other than black and if present is embedded within the
porous anodized structure and optionally may contain in addition
to, or of itself, a colored dye image also embedded in the anodized
porous structure so that a colored image or series of colored
images are obtained by any technique commonly utilized for
obtaining or transferring an image as by a photoresist,
lithography, offset or letterpress printing, mineographing, silk
screening, or painting by means of brush, roller or pneumatic or
hydraulic spraying a fully colored or panchromatic or black and
white information or pictorial display may be obtained which may be
backlighted to enhance or increase the contrast of said anodized
layer by laminating the layer to a suitable support and removing
the aluminum metal backing member as is illustrated in FIG. 5 or
FIG. 8, wherein a supporting layer is utilized or the laminating
material constitutes the sole supporting member. This particular
aspect of this invention is described by the following
examples:
EXAMPLE 36
A 24 .times. 18 inch unsealed, unsensitized, anodized aluminum foil
plate 0.003 inches thick, was coated with a resist material
commercially available from Horizons Research Incorporated. The
resist coated plate was then exposed through and in contact with a
separation negative to a 100 mj ultraviolet light source. The
exposed area was then fully cured by heating at 145.degree.C for 30
seconds whereupon the unexposed portion of the resist was then
removed by a brief spray rinse in water and dried, following which
a dye was applied to the exposed portion of the resist. This
procedure was repeated using a total of three separation negatives
and three resist coatings followed by a different colored dye
impregnation between each operation. In this manner a multicolor
color image was embedded in the anodized layer which was then heat
laminated face down to a polyester coated polyester film whereupon
the entire aluminum backing member was removed by etching in a
saturated aqueous solution of mercuric chloride.
EXAMPLE 37 (FIG. 21)
Three 18 .times. 24 inch unsensitized anodized aluminum foil plates
were exposed each to a separation negative and a separation dye
image applied to each one while being held in registry one to the
other, using the same scent described in Example 36. The panel
corresponding to the main background color was then laminated face
down to a clear optically flat polished glass substrate using a
room temperature cure, two part clear epoxy resin and the aluminum
backing member removed by etching in a concentrated hydrochloric
acid bath. The second foil sheet containing the second separation
image was then laminated face down to the first again using the
room temperature cure epoxy adhesive and the entire aluminum
backing member removed and so on to the third dye image. In this
manner a multicolor image was obtained which had a pronounced three
dimension effect when viewed with transmitted or reflected light
and which was suitable for outdoor display purposes.
EXAMPLE 38
A three color print was obtained on a 3 .times. 4 inch anodized
aluminum foil plate as described in Example 36. The foil plate was
then laminated face down to a cylindrical clear drinking glass
using a room temperature cure, clear epoxy adhesive. The aluminum
backing member was removed by etching resulting in a very
attractive decal which was not subject to attack by repeated
washings in a strong detergent, hot water or steam or other
ordinary household chemicals, or by abrasion and the like.
EXAMPLE 39
A photoresist material was applied to an unsensitized, unsealed,
anodized aluminum foil plate and selectively exposed and developed
in the same manner as that described in Example 37. Tne entire
plate was immersed in a dilute aqueous stannous chloride solution,
briefly rinsed in distilled water, and then immersed in a dilute
aqueous palladium chloride solution and vigorously rinsed under
running tap water. In this manner the selectively exposed anodized
porous surface is now selectively sensitized for the electroless
deposition of various metals. The well rinsed plate was then
immersed in an electroless nickel solution until a bright shiny
deposit of nickel was formed in the exposed anodized areas. The
excess resist material was then removed by immersing in a mixture
of ethylene glycol monoethyl ether and water, dried thoroughly,
then laminated face down to a cylindrical glass tumbler using a
clear, heat curable epoxy adhesive. The aluminum metal backing
member was then removed by etching. In this manner a very
attractive metallic design was imparted to the article which was
not subject to attack by repeated washings in various household
detergents or chemicals, hot water or steam, and in addition was
not prone to attack by abrasion or scratching, and had no tendency
toward tarnishing or attack by various oxidizing agents.
EXAMPLE 40
An unsealed anodized aluminum foil plate containing within the
anodized structure a continuous tone black silver image was
immersed in a dilute aqueous solution of lead acetate, lightly
rinsed with water and then immersed in a slightly stronger aqueous
solution of ammonium sulfate, then rinsed again with water which
resulted in white lead sulfate being precipitated in the anodized
porous structure throughout. After drying the foil plate was
laminated face down to a cylindrical glass tumbler using a heat
curable epoxy resin. The aluminum metal backing member was then
removed resulting in a very attractive matte black finish
containing the silver image wherein the continuous tone was
accentuated in the regions of lesser density and the areas in which
no silver was present were characterized by a very soft translucent
white coloration. As before, the article was not subject to attack
by hot water or steam, ordinary household chemicals or detergents,
abrasives or scratches or the like.
EXAMPLE 41
An unsealed anodized aluminum foil plate containing a continuous
tone black silver image was coated with a metallic blue dye which
was then superimposed on the black silver image as well as
distributed throughout and within the anodized porous structure.
The plate was then sealed in a commercial sealing bath of cobalt
and nickel acetate and dried thoroughly prior to laminating to a
cylindrical glass tumbler using a heat curable phenolic polyvinyl
butyrol adhesive at 350.degree.F for 20 minutes. The aluminum metal
backing member was then removed by etching and a very attractive
continuous tone black silver image accentuated by the metallic blue
dye present in the non silver image areas and being of a reverse
continuous tone.
EXAMPLE 42
A series of unsealed anodized aluminum foil plates containing a
photographically developed continuous tone silver image within the
anodized structure were each bonded to a cylindrical glass tumbler
using an epoxy adhesive each of which was filled with a Day-Glo
phenol formaldehyde pigment structure of differing color. Since the
epoxy was formulated to cure at room temperature the fluorescent
properties of the various pigments were unimpaired. The aluminum
backing member was removed in each case by etching and the result
was a strikingly pronounced continuous tone fluorescent dye image
effect which could be still further enhanced by backlighting of
each cylinder and was not subject to any of the aforementioned
modes of attack. In each case the amount of pigment utilized as
well as the adhesive thickness could be varied to provide a degree
of control over the fluorescent effect desired.
EXAMPLE 43
A small unsealed anodized aluminum foil plate containing a positive
image of indicia wherein the indicia were formed of non-image
anodized aluminum surrounded by the black silver image background,
was immersed in a dilute aqueous solution of barium chloride,
lightly rinsed, then immersed in a slightly more concentrated
aqueous solution of ammonium sulfate and then rinsed well and
dried. In this manner a white compound consisting of barium sulfate
was precipitated in the pores of the aluminum oxide layer being
superimposed upon the developed silver image. The plate was then
laminated to the sidewall of a black automobile rubber tire using a
Goodyear "Pilobond" adhesive and the aluminum backing member
removed by etching resulting in a white indicia marking being
strikingly delineated by the black photographically reduced silver
outline which now constitutes a very durable, abrasion resistant
flexible decal.
Alternately, selected areas of the aluminum backing member may be
removed as described in Example 2 to provide for selected areas of
transmitted light compared to areas using only reflected light,
thereby serving to enhance or reinforce certain areas or to provide
different sets of information, for example "open" as opposed to
"close" or "on" vs "off," when the transmitted portion is lighted.
A manner in which this description has been reduced to practice a
particular aspect to this invention can now be described as
follows.
EXAMPLE 44 (FIG. 7)
An unsealed anodized aluminum foil pate, 0.003 inches in thickness
and having a rectangular dimension of 8 by 11 inches was utilized
containing an anodized layer on one side only of approximately 10
microns in thickness within which was embedded a black
photographically produced silver image outlining non-imaged
portions of anodized aluminum in the form of indicia which in this
case formed the words "ON" and "OFF" and reverse reading with the
letter "O" being common to both words and the letters "N" and "FF"
being intermingled. The entire indicia pattern was then impregnated
with a blue dye designated "Sandoz Aluminum Blue B" by immersing
the panel in an aqueous solution of the dye for ten minutes at
150.degree.F, after which the plate was rinsed and dried. The plate
was then coated with a very thin layer of the PR 543 resist
material and dried. A negative transparency film was then placed
over the letter "O" and that portion of the second indicia forming
the combination letters "N" and " F" which consisted of a dot
pattern spelling "ON" the dots consisting of a square array with
each dot being approximately 20 microns in diameter, the edge of
which contacts the edge of the immediately adjacent dots. Those
portions of the combination letters "N" and "F" common only to the
letter "F" were void of a dot pattern whereas those portions common
only to the letter "N" were completely masked off. The resist was
then exposed through this dot pattern and cured as before and the
unexposed portions of the resist and dye removed by washing
thoroughly in water. The entire panel was then immersed in an
aqueous red dye solution designated "Sandoz Aluminum Bordeaux Red"
for 10 minutes at 150.degree.F after which the panel was rinsed and
dried and the cured resist coating removed by washing the panel in
a mixture of ethylene glycol monoethyl ether and water and then
dried. In this manner a mosaic colored design consisting of
alternate red and blue dots was obtained forming the letter "O" and
those portions of the second letter common to the letters "N" and
"F" whereas those portions of the letter "N" common to that letter
only were in red and those portions common only to the letter "F"
were solely in blue.
The obverse panel was three-eighths inches larger in both
directions than the colored indicia panel and of the same thickness
and consisted of highly reflective electroless nickel deposit
superimposed on the embedded silver image which in general outlined
a non-image area directly behind the indicia which contained
impregnated barium sulfate and consisted of a relatively large
conductive pattern in the form of two completely separated circuits
being separated by a thin line devoid of silver or deposited nickel
and also containing impregnated barium sulfate, in such a manner
that the maximum area of the panel contained the reflective nickel
film. A set of miniature tungsten lamps containing optical red
plastic filter caps were soldered into opposite corners on the
conductive pattern and a second set of lamps containing optical
blue filter caps were soldered into position at the opposite
corners. The panel was then mounted onto a light transmitting panel
containing oversized cylindrical bores within which the lamps were
inserted using a room temperature cure clear polyester potting
adhesive with the overlapping edge portions of the panel being
folded over the edges of the light transmitting panel. The indicia
panel was then laminated above the light transmitting panel using a
heat curable while translucent polyester double faced adhesive
after which the entire aluminum metal backing member surrounding
the panel was removed by immersing in a saturated solution of
mercuric chloride.
The colored indicia are now clearly visible surrounded by the
opaque black silver image as well as the conductive pattern on the
obverse panel to which external electrical connections were made by
inserting contacting pins in the appropriate positions and potting
into place. The contacting pins were then connected to an external
switch in such a manner that when the switch was in the "ON"
position the circuit containing the red colored lamps was activated
and the blue colored lamp circuit was deactivated and when the
switch was in the "OFF" position the circuit containing the blue
colored lamps was activated and the red lamp circuit was then
deactivated. The light emitting from the colored lamps are passed
through the light transmitting panel and diffusely reflected by the
white areas outlining the indicia of the reverse panel and directed
through the indicia portion of the obverse panel wherein red
colored light passes through those areas of the indicia containing
red dye and are blocked or absorbed by those areas containing the
blue dye, therefore the word "ON" appears in red. Conversely when
the circuit containing the blue illuminators is activated blue
light is passed through those areas containing blue dye and the red
dye prohibits the transmission of diffusely reflected light
therefore the word "OFF" is illuminated in blue light.
EXAMPLE 45
An unsealed anodized aluminum foil plate 0.003 inches in thickness
and having a rectangular overall dimension of 18 by 24 inches was
utilized, containing an anodized layer on one side only of
approximately 10 microns in thickness within which was embedded a
black silver image contained throughout except for those areas of
the indicia defining the words "NO. 1" at the top portion, the word
"READY" positioned immediately below the word "SPENT" occupying the
lower third of the long side of the panel, all three words being
left reading.
The indicia forming the word "READY" was instantly colored by
swabbing over the area with a blue colored dye designated "Sandoz
Acetol Blue" and the procedure repeated using a red dye designated
"Sandoz Acetosol Scarlet" to impregnate the indicia forming the
word "SPENT." The indicia panel was then laminated face down to a
one thirty-second inch thick translucent polyester panel sheet
using a clear double faced polyester heat laminable adhesive tape
and the aluminum metal backing member removed using the
hydrochloric acid-hydrogen peroxide etching procedure which now
forms the completed indicia panel.
A light transmitting panel similar to that utilized in Example 44
was prepared within which several additional sets of blue and red
colored miniature tungsten lamps were provided, with electric
current being supplied by the electroless nickel pattern which
surrounds the non-image or translucent portions of the indicia
placed directly in line with the indicia of the indicia forming
panel as described also in the previous example.
The above indicia panel was connected to the light transmitting
panel by placing a thin bead of a room temperature curing silicone
resin adhesive around the periphery of the panel and the two panels
held in position being separated by a small air space until the
resin had cured. This example works in the same manner as described
in Example 44, that is, when the blue colored light is activated
the indicia forming the word "READY" in blue will be illuminated in
blue light which will not illuminate the indicia forming the word
"SPENT" in red since the red dye in this case effectively prohibits
the transmission of blue light. When either the red or blue color
illuminators are activated the indicia forming the word "NO. 1"
will be illuminated.
EXAMPLE 46 (FIG. 22)
An anodized aluminum foil plate 0.005 inch in thickness was
utilized as described in Example 45, except the indicia panel as
well as the reverse panel and sides were fabricated from a single
sheet of anodized aluminum and the lamps soldered into place and a
connection pin was provided. The sheet was then folded into a
rectangular dimension such that it formed the final shape of the
panel desired except for one end. The folded over edge portion,
again excepting the one end, were sealed with a double face
pressure sensitive adhesive and the entire assembly turned on end
and held flat and parallel by a movable mold arrangement support
with the open end facing up. The interior of the panel was then
filled with a castable allyldiglycolcarbonate resin containing
approximately 3 percent by weight isopropyl percarbonate catalyst.
Since this casting undergoes 14 percent shrinkage during
polymerization, an excess of monomer material is applied to
compensate for this amount using the variable mold arrangement. The
filled mold was then placed in a hot air oven for 24 hours at
70.degree.C. The supporting mold was then removed and the cast
panel was given a post cure treatment of 115.degree.C for 2 hours
which serves to complete the cure, relieve strains and assure
dimensional stability of the finished panel. The open ends were
then folded over and secured in place with a double faced pressure
sensitive adhesive and an external connection made to the enclosed
circuit pattern terminals which was then wrapped with a plastic
adhesive tape and the panel immersed briefly in a 10 percent
aqueous sodium hydroxide solution, rinsed briefly in water, and the
entire exterior aluminum metal backing member removed by etching. A
completed edge illuminated panel similar to that of Example 45 is
obtained. It is evident that the sides and reverse panel need not
be etched if a strippable coating is first applied to those areas
prior to the etching procedure.
The products described in the preceding description and examples
have been indicated to be particularly suited to use in the
manufacture of edge lighted panels, for example, panels of the
types described in any of the following U.S. Pat. Nos. issued to
Hardesty: 2,795,069, 2,810,225, 2,821,800, 2,838,865, 2,866,911 and
2,945,313, the disclosures of which are incorporated in this
application by reference, and in many other edge lighted panel
constructions known in the art.
A related application entitled "Metal Plated Images" was filed in
the United States Patent Office on Oct. 22, 1971 in which claims
are included to some of the subject matter disclosed in the present
application. This application was given Ser. No. 191,635.
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