Multi-color electro-luminescent light strip and method of making same

A multi-color illuminated panel is made up of a decorative frontsheet having windows cut therein and which may include decorative patterns printed thereon, a transparent supporting sheet, which may also have decorative printing thereon, and a pre-wired backsheet in the form of a printed circuit board having multiple individual electro-luminescent light panel segments of different colors affixed thereto and electrically connected to traces on the circuit board, the electro-luminescent light segments of different colors emitting light which shines through corresponding windows and thereby provides a spectacular multi-color lighting effect.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the field of decorative lighting, and more 
particularly to an electro-luminescent (EL) light panel or strip having 
different colors and patterns, and to a method of making an 
electro-luminescent light strip or panel having different colors and 
patterns. 
2. Discussion of Related Art 
An electro-luminescent light panel or strip is a flexible enclosure which 
contains an electro-luminescent material, phosphor being a typical 
material, capable of emitting light when an electric current is discharged 
into or applied to the material. 
An example of a conventional electro-luminescent light panel is shown in 
FIG. 1. The panel shown in FIG. 1 includes at least two protective layers 
and/or coatings 1,2,10,11 on each exterior side of the structure 
1,2,10,11, electrode 3 and 8, leads 4 and 10 connected to the electrode 
layers by a bus bar 6, and a phosphor layer sandwiched between the 
protective outer layers and in contact with the electrodes. 
Such light panels have conventionally been limited, for reasons of cost and 
manufacturability, to a single color per panel or strip. While multiple 
colors are possible in such a panel, the multi-color effect can only be 
obtained by adding additional coatings or layers to the outside of the 
panels, which greatly increases the complexity of the manufacturing 
process, and prevents the light panels, despite their inherent 
attractiveness, from becoming competitive with alternative decorative 
lighting arrangements, including incandescent lighting, light emitting 
diode arrangements, and neon or fluorescent lighting for most 
applications. 
The problem of cost involves not only the cost of manufacture, but also the 
materials costs of the light panel itself and of the multiple coatings 
conventionally necessary to obtain a multi-color effect. In the majority 
of applications, it is not necessary to light the entire panel or strip in 
order to provide the desired effect, but manufacturing considerations 
often dictate the entire panel be uniformly lit, resulting in higher 
material costs. 
In addition to the above considerations, the use of bulk wiring in 
conventional electro-luminescent panel interconnections further increases 
their cost, and limits the range of potential applications. It is, for 
example, difficult to provide special effects such as motion or animation 
involving sequential turn on/off, chasing, or random fade-in/fade-out 
effects using conventional electro-luminescent panel arrangements, and 
thus LED panels are conventionally used for such purposes. 
Finally, electro-luminescent panels have traditionally been limited to 
applications which make use of their attractiveness in the dark, the 
panels themselves being relatively plain and not particularly attractive 
unless lit. To-date, therefore, electro-luminescent panels have simply not 
been competitive with other lighting and decorative systems in all but a 
few narrow single-color applications. 
SUMMARY OF THE INVENTION 
It is accordingly a first objective of the invention to provide a method of 
making an electro-luminescent light strip or panel which overcomes the 
limitations of the prior art by reducing the amount of costly coatings and 
electro-luminescent materials required to obtain a desired lighting 
effect, by reducing the complexity of the process required to manufacture 
such a panel, and by increasing the flexibility of colorings, patterns, 
and special effects obtainable in the panel for an interesting and 
attractive appearance both in darkness and daylight. 
It is also an objective of the invention to provide a simplified method of 
constructing an electro-luminescent light panel having the above-cited 
advantages over conventional electro-luminescent panels, including the 
capability of exhibiting a multiple colors, patterns, and special effects, 
for an interesting and attractive appearance both in darkness and 
daylight. 
It is a further objective of the invention to provide a multi-color 
electro-luminescent light panel in which the multiple colors are provided 
without the need for multiple coating arrangements, and yet which is in 
the form of a single discrete panel formed by a single exterior frontsheet 
and a single exterior backsheet. 
These objectives are accomplished, in a preferred embodiment of the 
invention, by providing a multi-color illuminated panel made up of a 
decorative frontsheet having windows cut therein, a transparent supporting 
sheet, which may also have decorative printing thereon, and a pre-wired 
backsheet on which are affixed discrete individual single-color 
electro-luminescent light panel segments, the electro-luminescent light 
segments being capable of having different colors and arranged to shine 
through the windows and provide a spectacular multi-color lighting effect. 
By using small localized electroluminescent panel segments, the materials 
costs for the electro-luminescent light panel is decreased while at the 
same time the design flexibility, and particularly the flexibility to 
choose different color patterns is significantly increased without a 
corresponding increase in manufacturing complexity. 
In a particularly preferred embodiment of the invention, the small single 
color segments are arranged at predetermined locations on a single 
pre-wired backsheet and affixed by a non-mechanical means such as 
double-sided adhesive tape or glue for ease of assembly and decreased 
cost. The segments are then secured between the backsheet and a protective 
frontsheet layer by applying a pressure roller and/or heat to join the 
back and frontsheets according to known and relatively inexpensive methods 
of joining together two layers of material. 
The protective frontsheet layer is preferably transparent and has affixed 
thereto a decorative frontsheet layer made of an attractive material such 
as leather or a high quality plastic such as polyvinylethylene (PVE) 
through which are cut or stamped openings at the locations of the small 
individual electro-luminescent light segments to permit the light from the 
segments to be visible from the front of the panel, and on which lettering 
or decorative patterns may be printed, painted, or silk-screened to form 
an arrangement which is attractive not only in the dark but also in 
daylight, which uses just enough of the electro-luminescent materials to 
obtain a desired effect, and which is simple to construct. 
Those skilled in the art will appreciate that, because of its flexibility 
and low cost, the multi-color light panel of the preferred embodiment will 
be useable in a wide variety of purposes for which conventional 
electro-luminescent light panels have previously been considered to be 
unsuitable, including advertising displays, signs, posters, greeting 
cards, and even fine artwork, and thus the electro-luminescent light panel 
described and claimed herein represents a significant and unexpected 
improvement over conventional electro-luminescent light panel arrangements 
.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 2 is a detailed perspective view of a particular electro-luminescent 
light panel which is intended to illustrate the principles of a preferred 
embodiment of the invention. Those skilled in the art will appreciate, 
however, that the specific patterns and structures shown in the drawings 
are intended to be exemplary only, and that numerous variations and 
modifications of the illustrated embodiment are possible, including but 
not limited to the variation shown in FIGS. 3 and 4. In fact, in a sense, 
it is the unique construction of the invention that makes possible the 
large number of possible variations and modifications. 
The principal components of the multi-color illuminated panel of this 
embodiment are a decorative front layer 73 having windows 72-83 cut or 
stamped therein, a transparent supporting front layer 84 which together 
with layer 73 forms a frontsheet for the panel, and which may also have 
decorative printing thereon, and a pre-wired backsheet 108 on which are 
affixed discrete individual single-color electro-luminescent light panel 
segments 85-93, the electro-luminescent light segments 85-93 being 
arranged to shine through the windows and provide a spectacular 
multi-color lighting effect. 
A typical individual light segment is illustrated in more detail in FIG. 5. 
The construction of the individual light segment shown in FIG. 5 and used 
in the preferred embodiment may be identical to the conventional light 
panel shown in FIG. 1, although those skilled in the art will appreciate 
that the construction and type of electro-luminescent light panel used may 
be modified without departing from the spirit of the invention. As 
illustrated, the light segment includes an outer covering 120 which 
encloses a pair of electrodes, a phosphor or similar electro-luminescent 
material, and a bus bar (not shown in this Figure). Extending from 
covering 120 are a pair of leads 121 and 122 which are to be connected to 
prearranged wiring on the backsheet 84 at locations 94 and 98-107 
illustrated in FIG. 2. 
In the preferred embodiment, as explained below, three different colors of 
electro-luminescence are employed, although those skilled in the art will 
appreciate that the a wide variety of differently colored 
electro-luminescent light segments are available and could be used in the 
preferred embodiment. In addition, it will be noted by those skilled in 
the art that, while most of the illustrated segments have a square or 
rectangular shape, segments 90 and 91 are in the shape of rabbits, and 
that the segments could easily be made in any desired shape, although the 
use of regular shaped segments is most economical. 
In a particularly preferred embodiment of the invention, the small single 
color segments 85-93 are affixed to the pre-wired backsheet 108 at 
locations 94 and 98-107 and affixed by a non-mechanical means such as 
double-sided adhesive tape or glue for ease of assembly and decreased 
cost. The segments are then secured between the backsheet and the 
protective frontsheet layer 84 by applying a pressure roller and/or heat 
to join the back and frontsheets according to known and relatively 
inexpensive methods of joining together two layers of material. The 
joining of the materials may also be facilitated by the use of adhesives, 
and/or by the use of the same material, which should be strong enough to 
provide support and protection for the light segments, but which may also 
be flexible if desired. An example of a suitable material is PVE. 
The protective frontsheet layer 84 preferably transparent and has affixed 
thereto a decorative frontsheet layer 73 made of an attractive material 
such as leather, foil, paper, or a high quality plastic such as PVE 
through which are cut or stamped openings at locations 74-83 corresponding 
to the locations 94 and 98-107 of the small individual electro-luminescent 
light segments to permit light, upon illumination of the segments, to be 
visible from the front of the panel, and on which lettering or decorative 
patterns may be printed, painted, or silk-screened to form an arrangement 
which is attractive not only in the dark but also in daylight, which uses 
just enough of the electro-luminescent materials to obtain a desired 
effect, and which is simple to construct. 
As illustrated, decorative frontsheet layer 73 includes the following 
cutouts, which may be augmented or enhanced by designs printed, painted, 
drawn, silk-screened or otherwise imprinted in the non-cutout areas of the 
sheet: 
(1) a message 79, which says "HAPPY VALENTINE"; 
(2) various hearts 75-83; and 
(3) cartoon rabbits 74 and 83. 
As noted above, the light segments corresponding to the cutouts are regular 
in shape, with the light segment 85 corresponding to the valentine's 
greeting having an extended rectangular shape. 
An alternative arrangement for the "HAPPY VALENTINE" message is shown in 
FIG. 4. As in the preferred embodiment of FIG. 2, the portion of the 
decorative frontsheet 73 through which the light from the 
electro-luminescent segment is to appear is cut or stamped to form letters 
38-51, collectively designated by reference numeral 37. However, in this 
embodiment, instead of a single electro-luminescent panel 85, a plurality 
of electro-luminescent panels 59-71 are included, each of which may be a 
different color if desired. 
Alternatively, those skilled in the art will appreciate that the lettering 
for the message may also be obtained, as shown in FIG. 2A, by including a 
single extended rectangular cutout (111) in decorative front panel 73 and 
forming the letters by applying an opaque pattern (110) to layer 84, 
silk-screening, painting, block printing, or the like. Similar variations 
can also be made to other parts of the frontsheet, particularly if the 
cost of the material of the decorative front layer is high, i.e., while 
the supporting front layer 84 is preferably made of a fully transparent 
material, and is performs the structural role of holding the individual 
small electro-luminescent segments in position against backsheet 108, 
layer 84 could also be printed with a design such as a cartoon or message 
on the outside surface to reduce the material cost of the decorative 
frontsheet layer 73 by cutting away the decorative layer to reveal 
patterns on the supporting layer 84. 
Examples of the manner in which the small single color segments 85-93 are 
used to provide a multi-color effect are as follows, although those 
skilled in the art will appreciate that the selection of colors depends 
solely on the aesthetic taste of the designer and not on any functional 
considerations: 
(1) the letters "HAPPY VALENTINE" are illuminated by purple colored 
segments at location 104 (or by multiple single color segments as 
illustrated in FIG. 4; 
(2) the two rabbits 74 and 83 are backed by pink a segment for rabbit 90 
and a white segment for rabbit 91 at locations 94 and 98; and 
(3) hearts 72-82 are lit by red segments 89-93 at respective locations 
99-107. 
In order to further simplify assembly and reduce costs, as well as 
providing for special effects, the backsheet 108 may be in the form of a 
printed circuit board for the electro-luminescent light segments which 
includes printed traces 95 made by well-known foil stamping or similar 
techniques, and may include appropriate switches to turn the segments on 
and off as well as connection terminals 96 and 97 for connecting the 
segments which may either be series or parallel connected, to a power 
supply (not shown). The use of a printed circuit board as the backsheet 
also makes it especially convenient to include circuitry for providing 
special effects such as sequential, rhythmic, or random on and off 
switching for the individual electro-luminescent light segments, in order 
to provide illusions of motion or otherwise further draw the attention of 
the viewer to the display. 
A particularly advantage feature of this arrangement, illustrated in FIG. 
3, is that the same backsheet can be used with a variety of different 
frontsheets, thereby further saving production costs. In the example 
shown, a single backsheet 26 including individual electro-luminescent 
light segments 27-29 is arranged to be used with at least different 
designs for a frontsheet 21, including one having a large printed heart 
and heart-shaped cutouts 23-25 corresponding to the locations of light 
segments 27-29, a second design made up of three star-shaped cutouts 31-33 
also corresponding in location to the location of light segments 27-29, 
and finally a third more abstract design also involving cutouts located to 
allow light from the individual light segments to shine through the 
frontsheet. 
As implied by the above description, the preferred method of making the 
above-described light panel involves the following steps, not necessarily 
in the order in which they would be performed: 
(1) cutting windows into the decorative front layer 73 and printing 
decorative designs thereon; 
(2) pre-wiring a circuit on backsheet 108 and marking locations for 
placement of the electro-luminescent light segments 85-93 corresponding to 
the locations of the windows; 
(3) affixing electro-luminescent light segments to the backsheet, using 
glue or double-sided adhesive tape, at locations which permit light from 
the light segments to show through the frontsheet and electrically 
connecting the segments to the pre-wired portions of the backsheet, for 
example by soldering; and 
(4) affixing the front layer 84 to the backsheet 108 using an adhesive, a 
pressure roller possibly in combination with the application of heat, or 
other known methods of joining two layers or sheets of material together, 
and affixing the decorative frontsheet layer 73 to the supporting 
frontsheet layer 84 using known methods depending on the materials of the 
respective layers. 
Having thus described a specific preferred embodiments of the invention in 
terms which will enable those skilled in the art to make and use the 
invention, it will nevertheless be appreciated that numerous variations 
and modifications are possible within the scope of the invention. 
Consequently it is intended that the invention not be limited by the above 
description or drawings, but rather that it be limited solely by the 
appended claims.