U.S. patent application number 09/403701 was filed with the patent office on 2002-02-21 for plastic shaped body with an integrated optoelectronic luminous element.
Invention is credited to CZAK, CHRISTIAN.
Application Number | 20020021086 09/403701 |
Document ID | / |
Family ID | 7827879 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020021086 |
Kind Code |
A1 |
CZAK, CHRISTIAN |
February 21, 2002 |
PLASTIC SHAPED BODY WITH AN INTEGRATED OPTOELECTRONIC LUMINOUS
ELEMENT
Abstract
The invention relates to a plastic shaped body with an
integrated optoelectronic luminous element and to a method for the
production thereof. To this end, translucent and cold-stretchable
plastic film is three-dimensionally formed at least in the area of
the luminous elements and subsequently sprayed with thermoplastic
synthetic material. The luminous elements are screen printed onto
the unshaped film in the form of luminous fields before the plastic
film is formed.
Inventors: |
CZAK, CHRISTIAN; (VIENNA,
AT) |
Correspondence
Address: |
CARL B MASSEY JR
KILPATRICK STOCKTON
1001 W FOURTH STREET
WINSTON SALEM
NC
27101
|
Family ID: |
7827879 |
Appl. No.: |
09/403701 |
Filed: |
December 29, 1999 |
PCT Filed: |
April 3, 1998 |
PCT NO: |
PCT/EP98/01958 |
Current U.S.
Class: |
313/503 ;
445/24 |
Current CPC
Class: |
B29L 2031/747 20130101;
B29C 2045/14237 20130101; B29C 2045/14737 20130101; B29C 45/14811
20130101; B29C 2791/007 20130101; H05B 33/12 20130101; B29K
2995/0036 20130101; H05B 33/10 20130101; B29C 51/10 20130101; B29C
45/1418 20130101 |
Class at
Publication: |
313/503 ;
445/24 |
International
Class: |
H01J 001/62 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 1997 |
DE |
197 17 740.9 |
Claims
1. Plastic form body with one or several integrated,
opto-electronic active luminous elements is characterized by at
least one translucent, cold-stretchable, three-dimensionally,
elastic, formed plastic foil (1), which is then back-injected with
thermoplastic plastic (3), and which, before the formation of the
luminous elements in the screen printing or by means of digital
printing processes is applied in the shape of luminous fields
(17).
2. Plastic form body, according to claim 1, is characterized by the
luminous fields (17), which are electro-luminescence fields that
basically consist of two electrically insulated electrodes; one is
a base electrode (10;13) and one is a cover electrode (7;14), which
is located between an electro-luminescence layer (8).
3. Plastic form body, according to claims 1 or 2, is characterized
by the electrodes (10,13; 7,14) and the electro-luminescence layer
(8), which is applied in the form of screen printing paste, and has
at least one of the dielectric layers or insulation layers (9)
located between the electro-luminescence layers (8) and the base
electrode (10;13), and this screen printing layer (7-11) is
formable at an operating temperature below the heat distortion
temperature of plastic foil (1).
4. Plastic form body, according to one of the claims 1 through 3,
is characterized by the electro-luminescence coating (8) that
consists basically of organic or inorganic substances, which can
take the form of a fine powder and/or is micro-encapsulated, and
therefore, wide-ranging water vapor sensitive elements with
diameters of 10 to 60 .mu.m to which respective plastic formable
and dielectric high-quality screen printing colors are added.
5. Plastic form body, according to one of the claims 1 through 3,
is characterized by the plastic foil (1) that is back-injected on
the inner side and/or outer side with thermoplastic plastics
(3).
6. Plastic form body, according to one of the claims I through 4,
is characterized by the plastic foil (1) whose graphic design takes
the shape of a sandwich on the inner side and/or outer side with an
additional thermoplastic foil (12).
7. Plastic form body, according to one of the claims 1 through 6,
is characterized by the wide-ranging transparent and electrical
conducting cover electrode (7) that consists of so-called
Indium-Tin-Oxide (ITO) paste.
8. Plastic form body, according to one of the claims 1 through 7,
is characterized by the plastic foil (1) of the cover electrode
that has the form of an ITO-sputter layer (14) and/or reflective
semi-transparent layers, and these wide-ranging transparent cover
electrodes (14) are printed (pressed) in the area of stronger
deformation and/or in the area outside the luminous fields (17) by
means of an electric conducting polymer paste.
9. Plastic form body, according to one of the claims 1 through 8,
is characterized by a metallized, transparent and very thin foil
(13) (instead of an insulation layer [9] and the silver paste base
electrode [10]) that is laminated on the electro-luminescence
coating (8) or, respectively, on the cover layer (11).
10. The process to produce a plastic form body, according to one of
the claims 1 through 9, is characterized by the following steps:
Prepare a transparent, cold-stretchable, thin plastic foil
substrate; Deposit a graphic shaping (design) in the form of an
opaque (covering) and/or translucent screen print formation;
Deposit a wide-ranging transparent, electric-conducting cover
electrode layer; Deposit an electro-luminescence coating; Deposit
an insulating, dielectric layer; Deposit an electric-conducting
base electrode layer; Three-dimensional formation of the plastic
foil substrate from single or multiple printed panels; Stamping out
the single panel.
11. The process to produce a plastic form body, according to the
claims 1 through 9, are characterized by the following steps:
Prepare a transparent cold-stretchable thin plastic foil substrate
that covers the entire surface on the inner side with an ITO-layer
and/or reflective semi-transparent layers in sputter processes;
Deposit a graphic shaping in the form of an opaque (covering)
and/or translucent screen printing formation; Deposit an
electro-luminescence layer; Deposit an insulating, dielectric
layer; Deposit an electric-conducting base electrode layer;
Three-dimensional formation of plastic foil substrate from single-
or multiple printed panels; Stamping out the single panels.
12. Process, according to claim 10 or 11, is characterized by the
formed plastic foil substrate that is placed in the injection
molding die and is back-injected with suitable thermoplastic
plastic; whereby, the electrical connection surface for the
electroluminescence electrodes and, if applicable, the window,
stays recessed or the electrical connection surfaces with inserts
and/or additional components in the form of electric conducting
contact elements and/or foil cables that are led outwardly.
13. Process, according to one of the claims 10 to 12, is
characterized by the three-dimensional formation of the plastic
foil substrate by means of isostatic high pressure formation with a
pressure of the printing (pressure) fluids greater than 20 bar
resulting in a warming of the operating temperature below the
distortion temperature of plastic.
14. Process, according to one of the claims 10 to 12, is
characterized by the three-dimensional plastic formation resulting
from the insertion of the plane unformed plastic foil substrate
with an injection mold die; whereby, the injection mold die is
warmed to an operating temperature lower than the distortion
temperature of plastic and the shaping by mainly mechanical shaping
and, finally, the end shaping that results from the thermoplastic
injection compound or mainly by the thermoplastic injection
compound itself.
15. Process, according to one of the claims 10 to 12, is
characterized by the plastic foil substrate that is formed
three-dimensionally by a mechanical stamping process and so is
inserted pre-shaped into an insertion mold die.
16. Process, according to one of the claims 10 to 15, is
characterized by an intermediate step on the base electrode layer
in which a screen printing layer is applied based on watery
polyurethane dispersion and/or polyurethane color containing
solvent to optimally bind the thermoplastic plastic compound;
whereby, the electrical connecting surfaces for the
electro-luminescence electrodes and, if applicable, the window stay
recessed.
17. Process, according to one of the claims 10 to 16, is
characterized by the screen printing of the electro-luminescence
layer that is mixed next to various electroluminescence pigments,
as well as daylight luminous (fluorescent) pigments.
18. Process, according to one of the claims 10 to 17, is
characterized by "steerable" luminous fields that are nested and
separated and can be produced so that the base electrode connection
of a inner-lying luminous field can be guided outwardly by silver
conducting paste, and thereby, additional local insulating pressure
(print) layers are placed on the outwardly lying electrode
connections so that these inner-lying base electrode connections
can be guided outwardly electrically insulated, and thus, the base
electrode connections that are designed in this manner can be
triggered electrically separated.
19. Process, according to one of the claims 10 to 18, is
characterized by a thin thermoplastic foil laminated on the base
electrode layer and so, in cases of back-injection by means of
thermoplastic plastics, a higher temperature load and especially
inconvenient injection positions with correspondingly high
temperatures can be utilized.
20. Process, according to one of the claims 10 through 19, is
characterized by the injection with thermoplastic plastics that can
take place not only on the inner side, but also on the outer sides
or, respectively, also from both sides, so that optical lens
effects and lighting cable effects can be achieved; especially
thermoplastic plastics based on polycarbonate (PC) and
polymethylmethacrylate (PMMA) as well as transparent
acrylonitrile-butadiene-styrene (ABS), polyamide (PA) and
polypropylene (PP) plastics, as well as respective mixtures of the
mentioned plastics, can be used.
21. Process, according to one of the claims 10 to 20, is
characterized by, that instead of the deposit of an insulating
dielectrical layer and the base electrode layer by means of a base
paste, only the geometry for the purpose of strengthening the
ITO-electrode and its electrical connection is pressed (printed),
and finally, with or, respectively, without watery polyurethane
dispersion coating, a metallized transparent thin foil is laminated
on the backside, which produces the dielectric and the base
electrode, including reflector.
22. Process, according to one of the claims 10 to 21, is
characterized by the monitoring and operation control of the
ITO-screen printing coating's positioning since it is, to a large
extent transparent and, therefore, difficult to identify and its
positioning to the silver paste printing (pressing) results from
electrical contact pins that the predetermined test geometry comes
into contact with the geometrically exact electrical measuring
adapter and that only a positive signal is given whenever the
nearly transparent, but electrical conducting ITO-screen printing
geometry is brought within predetermined tolerances so then the
surface resistance of the ITO- and silver pastes test geometry is
determined and these measured values are used for process- and
operations control so that, additionally, by means of
correspondingly sized electrical testing pins on a suitable test
geometry, the puncture strength of the insulation pressure (print)
and the electro-luminescence pressure (print) is monitored and
recorded; whereby, the drying state of the layer construction is
controlled and the electrical capacity value of the test geometry
is measured and evaluated against the predetermined tolerances, and
this process is made with certain requirements of the surroundings,
such as controlled humidity and temperature.
Description
[0001] The present invention is a plastic form body with
graphically designed surfaces and integrated electro-luminescence
elements (EL elements). For example, graphic and
electro-luminescence structures are placed on transparent and
cold-stretchable thermoplastic plastic foil by means of silk screen
printing (serigraphy), then subjected to a pushing isostatic
high-pressure deformation, stamped and placed in an injection mold
and back-injected generally on the inner wall by means of suitable
thermoplastic plastic resulting in a three-dimensional plastic form
component with integrated EL luminous fields.
[0002] The DE 44 30 907 A1 makes a three-dimensional
electro-luminescence indicator based on an electro-luminescence
lights integrated in a three-dimensional formed body. The preformed
electro-luminescence lights are formed in a whole piece on a
substrate. The disadvantage with this is the separate design of the
aforementioned light transmitting layer and the
electro-luminescence light and their exact positioning to each
other that results in an expensive and costly production
process.
[0003] A similar three-dimensional electro-luminescence indicator
is made known with WO-A-94/14180. Here also, prefabricated, foil
formed electro-luminescence lights are applied on carrier material
and can be formed together. This has the disadvantage that a
separate design of the light transmitting layer of the carrier
material and the electro-luminescence light and an exact
positioning of the EL-lights in the carrier material is necessary,
which makes the production expensive and cost-intensive.
[0004] Usually the decorative foils are formed after the vacuum
process or the compressed air process to a three-dimensional
deep-drawing formed body. Then the graphically designed
thermoplastic foils are heated to a temperature above the
material's heat distortion temperature so that they can be shaped
with relatively little pressure (such as vacuum). These vacuum- and
compressed air processes can be used very efficiently with
graphically non-critical or neutrally designed foils and form
bodies, and function with vacuum processes at a medium pressure of
less than 0.95 bar and with compressed air processes at an
operating medium pressure of less than 6 bar.
[0005] Form components that require exact positioning of
graphically designed elements and a very precise image with
patterns and/or a great contour sharpness, and which must have a
precise form after the deep-drawing process, the procedures of the
isostatic high pressure forming according to DE 38 40 542 C1 (also
in a somewhat limited way, the so-called hydro-forming) offer
advantages.
[0006] The production of these types of electro-luminescence fields
in connection with the graphic design, must take the very precise
positioning of the individual presses and processes together into
consideration. The positioning of the nearly transparent ITO-paste
graphics, especially, presents a fundamental criterion of quality.
U.S. Pat. No. 5,583,394 makes a procedure of recording known that
provides invisible positioning markers in a visible light, which,
by means of a corresponding light source, are identified with an
ultra-violet light for respective reading sensors and, thus, make
an exact positioning possible. The disadvantage is that these
registration marks can only be applied with additional operating
steps and used only with special light sources and special
positioning sensors.
[0007] Electro-luminescence screen printing pastes are generally
made up of inorganic substances and, here again, are very pure ZnS,
CdS, Zn.sub.xCd.sub.1-xS, etc. Compounds of the II and VI group of
the periodic system are of importance that generally are doped or
activated with Cu, Mn, Ag, etc. Normal colors are yellow, green,
green-blue, blue-green and white.
[0008] Respective to the state of technology, these types of
luminescence pigments can be microencapsulated with diameters of
typically 15 to 60 .mu.m in order to be added to various silk
screen printing inks (colors), or non-encapsulated, certainly
taking the special hygroscopic characteristics of the ZnS pigments
into consideration. Fixing agents are used that, on the one hand,
provide good adhesion for the so-called ITO-layers, continue to
insulate well, reinforce the dielectric, in order to improve the
puncture or disruptive strength with high electrical field
strengths and, additionally, have a good water vapor block and so
additionally protect the phosphorous pigments to lengthen their
life expectancy.
[0009] Generally, phosphorous pastes of these types are put on by
screen printing or other coating procedures, such as brushing,
rolling, coil coating, etc. on transparent plastic foils or glass,
which again have a wide transparent electric conducting layer and
with it the electrodes for the visual side. Finally, the dielectric
and the back-side electrode are produced by printing (press)
techniques and/or laminating techniques.
[0010] The usual ITO-paste layers (or also tin oxide coatings,
etc.) applied by screen printing, however, have the advantage of
extensive random geometrical design possibilities, but the
vapor-deposited or sputter-deposited transparent and
electrical-conducting layers still have the disadvantage of having
less optical transparency or translucency and, furthermore, have a
much lesser degree of conducting capacity, of at the most some 100
Ohm per square in comparison to some less than 10 Ohm per square
with ITO-polyester foil or some less Ohm per square with ITO-coated
glass. But the glass can have pastes added (for example,
In.sub.2O.sub.3/SnO.sub.2), which must, however, be fired at over
500.degree. C. and, therefore, can already deliver with a 0.25
.mu.m film strength, an optical transparency of greater than 95%
and a conducting capacity of a single layer is from 500 to 1000 Ohm
per square.
[0011] The purpose of the present invention is to produce a
three-dimensional graphically designed plastic form body with
integrated electro-luminescence elements economically, with a
longer life expectancy, increased luminous intensity and guaranteed
performance regardless of the existing electric power supply.
[0012] In the framework of the present invention it has been
determined that the new types of electro-luminescence screen
printing inks (colors), new types of ITO (Indium-Tin-Oxide) colors,
and new types of insulation and dielectric colors, together with
the printing format can be applied, and then the high-pressure
formation and the back-injection can be completed by means of
thermoplastic plastics by following several ground rules without
impairment to the function of the electro-luminescence
elements.
[0013] According to the invention, the previously discussed
procedure of the isostatic high-pressure formation is sufficient
for forming the plastic components. So-called cold-stretchable
plastic foils are provided with printing ink (colors) that,
together with an operating temperature below the distortion
temperature of the thermoplastic foil's plastic, completes a
push-type forming operation to a three-dimensional plastic form
component with greater image precision.
[0014] Advantageously, isostatic high-pressure forming, especially
the push-type stamping of the plastic components with preferably
several 100 bar compress air (typically 50 to 300 bar), very short
cycle times with outstanding controlled and even formation, which
results in greater image accuracy and, furthermore, produces the
same types of formed components with less heat (which means the
time-consuming cool-down phase is discontinued), outstanding
dimensionally stable formed bodies and constant contours (which
remain the same), which is really essential for the final stamping
process and the insertion into the injection molding die,
increasing the quality.
[0015] Other processes for forming the plastic foil
three-dimensionally are also possible (for example, mechanical
shaping or mechanical stamping methods). A re-forming of the
plastic foil placed in an injection molding die can itself result
from the injection of the thermoplastic plastic material.
[0016] The present invention is also based on the cognition that
for a product of this type, known screen printing pastes with
phosphorous pigments, especially in the microencapsulated form (but
also in the non-encapsulated form) based on respective doped
compounds of the II and VI groups of the periodic system,
especially in forms with Cu, Mn, Ag, etc., doped ZnS pigments in
combination with special cold-formable polycarbonate substrate or
the various mixtures of polycarbonate and polyethyleneterephthalate
(PETP) or polyalkyleneterephthalates are very suitable. Mixtures of
additional luminous colors, especially those that, through the
electroluminescence radiation for light excitation and release of
respective radiation with wide ranges of discretionary spectrals
(as narrow banded wave-length peaks) work very positively and
effectively.
[0017] In another development of this procedure, the color printing
can be imbedded sandwich-like between two layers of foil material.
This results in less problems with the back-injection of
thermoplastic plastics, which in this case of color printing, are
better protected by the additional foil against distortion and
melting in the injection area.
[0018] In another typical embodiment, a layout of a luminous field
has not only two electrical connections, but many fields; for
example, with various color luminous fields, such as lettering
and/or symbols.
[0019] In relation to the necessary position exactness, the
individual printings have been established within the framework of
the present invention; that the registration of the various layers
and processes can be realized manually in general by means of
registering marks in visible luminous areas (and also
automatically), and that each layer based on the nearly transparent
ITO-paste can be controlled and registered very well concerning the
preciseness of the position and the constancy of the process by
means of electrical test configurations in connection with
conducting paste structures. Additionally, the allowable surface
resistance and/or contact or transition resistance of the ITO-paste
contacts to the conductor will be evaluated and recorded.
[0020] The invention at hand will be explained more closely by
several embodiments and should, thereby, emphasize the
invention-related characteristics:
[0021] Shown:
[0022] FIG. 1: a section through a typical three-dimensional
plastic form body with EL-luminous fields;
[0023] FIG. 2: an enlarged detailed section of FIG. 1;
[0024] FIG. 3: a section through another typical three-dimensional
plastic form body with EL-luminous fields;
[0025] FIG. 4: an enlarged detailed section from FIG. 3;
[0026] FIG. 5: a section through another embodiment of a
three-dimensional plastic form body with EL-luminous fields;
[0027] FIG. 6: a section through another embodiment of a
three-dimensional plastic form body with EL-luminous fields;
[0028] FIG. 7: a section through another embodiment of a
three-dimensional plastic form body with EL-luminous fields;
[0029] FIG. 8: a section through a modified embodiment of a
three-dimensional plastic form body with EL-luminous fields;
[0030] FIG. 9: a section through a three-dimensional plastic form
body with EL-luminous fields, but in this case, the injection
occurred from the outside; that is the three-dimensional decorative
foil component is applied to the core of the injection mold;
[0031] FIG. 10: an overview of a test geometry to check the
preciseness of the positions of the various pressure (printing)
geometries and especially the electrical conducting and nearly
transparent (and therefore difficult to identify) ITO-screen
printing geometry;
[0032] FIG. 11: a section through the system according to FIG.
10;
[0033] FIG. 12: an overview of the three-dimensionally designed
plastic form body with graphically designed surface and
electro-luminescence luminous fields.
[0034] According to FIG. 1, a typically 100 to 300 .mu.m thick and
transparent foil (1), made preferably of polycarbonate, such as
polycarbonate-polyester mixture, with specification-determined
surfaces (as, for example, high gloss finish or satin matte finish)
provided on the inner side with graphic print (press) (2),
preferably the screen printing process and the respective screen
printing inks are sufficient for application. However, a
combination of other printing processes (for example,
offset-printing for graphic designs) can be used. Digital printing
processes especially (such as, for example, ink jet processes) are
fundamentally suitable. In this graphic printing (2), luminous
fields (17) are imbedded, which, likewise (for example, in screen
printing process) can be applied to the inner side of the foil (1).
In the next step the printed decorative foil (1) is subjected to a
push-type isostatic high-pressure forming in order to attain its
pre-determined three-dimensional shape. Finally, the formed foil
(1) with thermoplastic plastic (3) is back-injected. The contact of
the electro-luminescence fields (17) follows from a released
contact surface (6).
[0035] FIG. 2 shows an enlarged detailed section of the decorative
foil-injection mold body according to FIG. 1. In the presented
case, the first printing step of the graphic design (2) with opaque
(covering) and transparent or translucent colors is completed (that
is, applied to the foil material [1]). Finally an extensive
transparent cover electrode (7) (for example, in the form of an
ITO-screen printing paste) and the desired structure are applied.
On this ITO-layer (7), the electro-luminescence pastes (8) are
pressed in predetermined structures; whereby, not only an
electro-luminescence paste (8) can be used with an
electro-luminescence color, but also with many different radiating
EL-colors. The EL-colors can especially be mixed with daylight
luminous (fluorescent) colors in order to achieve the desired color
effect when activating the EL-fields (17). Furthermore, these
EL-elements (7) can be used with various circuitry wiring systems,
especially with the separate design of the silver conducting paste
electrodes (7). Finally on the EL-paste printing (7), insulation
printing colors (9) are usually achieved in two printing processes
with varying screens to prevent marks or defects and to produce the
so-called dielectric.
[0036] Usually these insulation pastes (9) are white in color and,
therefore, have a reflection effect for the EL-radiation.
[0037] In connection to these insulation layers (9), a silver
conducting paste structure (10) is pressed on, thus producing the
base electrodes.
[0038] Normally the surrounding ITO-paste pressing is
simultaneously reinforced in what is generally described as the
"Bus-bar" technique, so that an even and constant electrical field
strength can be attained over the total EL-luminous field (17).
Furthermore, the printing of the silver paste (10) also strengthens
the connecting surfaces of the ITO-electrodes (7), but these
reinforcements are understood in the sense of the reduction of
electrical surface's resistance.
[0039] Frequently it is advantageous to cover these various
screen-printing layers (7-10) additionally with a polyurethane
dispersion coating (11) in order to subsequently maintain an
optimal connection of the various thermoplastic injection mold
compounds. These cold-stretchable and graphically designed
EL-decorative foils (1) are usually subjected to multiple uses of a
push-type isostatic high-pressure forming and for this purpose, are
typically warmed from 40.degree. C. to 80.degree. C. This warming
is, however, certainly below the heat distortion temperature of
thermoplastic plastics of the decorative foil (1), because
otherwise there would not be such a high degree of image accuracy
of the deep-drawn printed picture.
[0040] In connection to the deep-drawing process, there is an exact
contour stamping of this three-dimensional object and it is then
placed in an injection mold die, and in the presented case is
back-injected by means of a suitable thermoplastic plastic (3)
mentioned in the beginning. Therefore, the selection of the
injection site on the form must be made very carefully and the
graphic design must be taken into consideration in order to prevent
distortions, deviations and re-melted spots.
[0041] Generally the connecting places for the EL-luminous fields
(17) are already kept free in the injection mold die, so that the
contacts of the EL-electrode connections (6) take place by means of
spring finger contact, crimping or electrical conducting tape.
Often the silver conducting paste connecting surfaces are still
additionally subjected to by passive, electrical conducting layers
in relation to the screen printing processes and so attains
increased protection again oxidation, resulting in a longer life
expectancy of these connections.
[0042] In another development of this embodiment, electrical
connecting elements can also be crimped or cramped in the
three-dimensionally formed decorative foils and this unit can be
placed together or also behind each other in the injection mold die
and be back-injected; therefore, attaining extreme mechanical, as
well as electrical, load-bearing connection elements for the
EL-luminous fields.
[0043] FIG. 3 shows, that in addition to the previous embodiment, a
thermoplastic plastic foil (12) can be laminated on the underside
of the graphically designed EL-decorative foil (1).
[0044] The adhesive bond can, depending on the required
specifications, achieve a thermoplastic hot-melt screen printing
coating by the screen printing technique of a polyurethane
dispersion coating; that the additional thermoplastic foil (12) can
be applied by a high melting process to bond with the graphically
designed EL-decorative foil (1) or this thermoplastic foil (12) can
have a corresponding additional coating (for example, a
corresponding hot melt coating) and can by a lamination process
attain a sandwich-type bonding foil.
[0045] The advantage of this additional foil on the inner side is
that the graphic and color design of the decorative foil (1) has
greater protection on the injection side of the injection mold die
and permits, especially the realization of critical geometries that
often have inconvenient choices of injection positions, which would
result in high injection temperature defects and color distortions
in the injection sites, which can be extensively prevented by this
additional foil.
[0046] FIG. 4 shows an enlarged section through the embodiment,
according to FIG. 3. The sequence of the applied layers correspond
basically to FIG. 2. However, an additional thermoplastic plastic
foil layer (12) is applied over the described layer succession
(7-11).
[0047] According to FIG. 5, instead of the insulation layer (9) and
the back electrode layer (10), a metallized plastic foil (13) is
laminated on by means of screen printing. The adhesive bond can,
depending on the required specifications, by screen printing
technique of a polyurethane dispersion coating (11), attain a
thermoplastic hot melt screen printing coating, the additional
metallized foil (13) can be applied by a high melting process to
bond with the graphically designed EL-decorative foil (1) or this
metallized foil (13) has a corresponding additional coating (for
example, a respective hot melt coating) and can by a lamination
process result in a sandwich-type bonding foil. The advantage of
this embodiment lies in the smaller amount of printings
(pressings), in the higher quality of the insulation layer and the
bonded good formability. The fundamental disadvantage of this
embodiment lies in the limited potential to trigger the EL-luminous
fields (17). Generally in this case only a common "steerable"
EL-luminous element (17) is formable and, furthermore, this type of
embodiment shows no cost-effective solution with regard to energy
supply, since the total surfaces work extensively and not only
individual selective surfaces. This disadvantage could in this
respect be used in another embodiment since the usual dielectric
layers (9) with the second screen printing process have barely more
than 20 to 30 .mu.m thickness and metallized plastic foils must be
laminated on with this thickness in order to achieve the same kind
of electrical supply some 10.sup.6 volt/cm on an electric field
strength for the purpose of EL-excitation. This special embodiment
is only typically 50 .mu.m thick and back-sided metallized plastic
foil (13) is used; the three-dimensional design is selected so that
only in the areas of desired EL-excitation, a stretching of the
materials (for example, around 100%) occurs and, through which,
this as dielectric functioning layer, is reduced by half and so
with a normal EL-distribution voltage builds up a sufficiently high
electric field so that EL-excitation can take place in these
selective areas.
[0048] FIG. 6 shows instead of the ITO-paste coating (7) of the
decorative foil (1) by means of screen printing, a transparent
decorative foil with ITO-sputter coating (14) and/or reflective
semi-transparent layers. This embodiment has the fundamental
advantage that this type ITO-coated transparent foil (14) has a
very high optical transparency, typically in areas greater than 85%
up to 95% and, additionally, offers very small surface resistance
values, typically in the area of 100 to 1000 Ohm per square. In
this way the EL-luminous element (17) can achieve a higher optical
luminous intensity with also correspondingly less size.
[0049] The disadvantage, however, beside the high price for this
type of coated plastic foil (14), is the complete flatness of the
electrical conducting layer and the small level of formability.
[0050] The problem with regard to the limited formability without
electrical interruption can, to this extent, be solved as the usual
EL-fields (17) in any case usually don't have strong
three-dimensional forms and in the cases of strong formations, the
electrical conducting capacity's so-called "Bus-bars" (that are in
general silver paste structures) are used. These electric
conducting polymer pastes are, however, relatively good plastic and
formable and can produce a protected contact for this transparent
cover electrodes. Moreover, no additional printings (pressings) are
necessary because by corresponding designs of the insulation
structures of these ITO-structures, reinforced conducting paste
structures can simultaneously occur with the base electrode
pressing (printing).
[0051] According to FIG. 7, instead of the ITO-paste coating (7),
the decorative foil (1) by means of the screen printing, a
transparent decorative foil (1) is used with the ITO-sputter
coating (14) and/or reflective semi-transparent layers and,
additionally, as with the previous embodiment, a thermoplastic
plastic foil (12) is laminated on the underside of the graphically
designed EL-decorative foil.
[0052] In FIG. 8, instead of the ITO-paste coating (7), the
decorative foil (1) by means of screen printing a transparent
decorative foil (1) is used with ITO-sputter coating (14) and/or
reflective semi-transparent layers and instead of two-stage
insulation printing (pressing) (9) and its silver paste printing
(pressing) (10), a metallized thermoplastic plastic foil (13) is
laminated on the underside of the graphically designed
EL-decorative foil (1).
[0053] FIG. 9 shows the injection of the decorative foil (1) with
thermoplastic plastic (3) can also take place from the outside;
that is, the three-dimensional decorative foil component (1) is
applied on the injection mold die core. For this, the sprayed-on
thermoplastic plastic (3) has corresponding notches (16) in the
area of EL-luminous (17) in order to allow the light to emit out or
at least in the area of the EL-luminous surfaces (17) to be formed
transparent or translucent.
[0054] FIG. 10 is an overview of a test geometry to check the
position preciseness of the various pressure geometries and,
especially the electric-conducting and the nearly transparent and
therefore, difficult-to-identify ITO-screen printing geometry. On a
carrier substrate [for example, a foil (1)] according to the
previously described process method, an electro-luminescence
element is pressed on. On the basis of a typical embodiment there
are four connection surfaces (18) (for example, made of silver
conducting paste); whereby, two surfaces are each for the
ITO-structure (19) and two surfaces are each for the silver, such
as conducting paste structure (20). The connection surfaces (18) of
the ITO-paste structure (19) are reinforced with silver paste so
that a point contact finger (21) can reach a secured electrical
contact, which, additionally, is relatively non-critical from the
standpoint of its position. By special selection of the geometry,
almost every determined tolerance of the diverse press structures
is checked very easily by this electrical test adapter and
recorded. So, the various structures must simply be formed
respective to the checked tolerances (for example, always be
printed (pressed) with 0.1 mm or also 0.2 mm projection). Should,
however, an error in the positioning in the individual press
process take place, the application of the respective stress test
will reveal the amounts of resistance and these can very easily be
coordinated to the particular errors. Furthermore, these electrical
test geometries can also check the insulation printing (pressure)
(22) and the EL-printing (pressure) (23) as to their positioning
preciseness, and additionally, can also conduct insulation tests
and surface resistance tests. Moreover, on the basis of these test
geometries, certain selected EL-potential (stress) and optically
the luminous field (24) can also be checked. Furthermore, this
EL-luminous field (24) can also be checked with fully automatic
color measuring sensors, such as intensity measuring sensors, for
required specification values.
[0055] FIG. 11 shows a section of the system, according to FIG. 10,
again.
[0056] FIGS. 12 show examples of three-dimensional surface forms
with built-in electro-luminescence elements, in which EL-elements
for dial illumination, functional indicators or others are
placed.
Drawing Legend
[0057] 1. Plastic foil (decorative foil)
[0058] 2. Printed (pressed) coating (for graphic design and
EL-structure)
[0059] 3. Back-injection (thermoplastic plastic)
[0060] 4. EL-light emission range (without back-injected
plastic)
[0061] 5. EL-light emission range (with back-injected plastic)
[0062] 6. Bonding of the diverse EL-electrodes
[0063] 7. ITO-paste printing (pressing)
[0064] 8. El-paste print (including various daylight luminous color
mixtures)
[0065] 9. Insulation printing (pressing) (=dielectric,
insulator)
[0066] 10. Silver paste print (press)
[0067] 11. Polyurethane dispersion coating
[0068] 12. Thermoplastic plastic foil
[0069] 13. Metallized thermoplastic plastic foil
[0070] 14. ITO-sputter layer
[0071] 15. EL-light emission range (with front-sided plastic
injection)
[0072] 16. Notch
[0073] 17. Luminous fields
[0074] 18. Connection surface
[0075] 19. ITO-structure
[0076] 20. Conducting paste structure
[0077] 21. Contact finger
[0078] 22. Insulation printing (pressing)
[0079] 23. Electro-luminescence print
[0080] 24. Luminous field
[0081] *ITO=Indium-Tin-Oxide
[0082] *EL=Electro-luminescence
* * * * *