Note: Descriptions are shown in the official language in which they were submitted.
~8479
This invention is directed to a new and improved sheet connector
or the like useful for coupling contacts of a first electrical device to the
contacts of a second electrical device.
It is still conventional practice to couple contacts of one device
to the contacts of a second device by soldering wires to the contacts. More
recently other schemes have been proposed such as a plurality of electrically
conductive plastic or rubber pads supported by an insulator, e.g., along
slots on the sides thereof or in holes formed therein. In this case the
contacts of the devices to be connected are positioned on opposite ends of
the pads and the assembly is then held together in a conventional manner.
While the aforementioned schemes are quite useful they are expensive
due to the costs associated therewith. Obviously soldering is time consuming
and thus labor costs are high. In the second scheme manufacturing costs are
high because of the steps needed to construct the insulator support and to then
fill the slots or holes thereof in a molding process.
Accordingly a new and improved connector was needed which would be
comparatively ine~pensive in terms of materials used as well as in the cost
of manufacture.
The present invention provides a connector which is both simple and
inexpensive to manufacture and extremely simple to use in order to couple
contacts of one electrical device to contacts of a second electrical device.
The oonnector of the present invention can be termed an isolated path
connector in that it exhibits a low through resis~ance in a volume between al_
igned opposing surface contact of electrical contacts on opposite sides of the
sheet and exhibits a higher isolation resistance in all volumes thereof at an
isolation distance greater than about the thickness of the sheet. Thus elect_
rical contacts positioned apart from each other on the same side of the sheet
at a distance greater than about the thickness of the sheet are electrically
isolated from each other even though another contact on the opposite side of
the sheet and aligned ~ith respect to one of the first of said contacts will
- 1 _
~L0~847~
be electrically coupled together.
In view of the above mentioned properties of the connector of this
in~ention it is now possible to make electrical contact bet~een a plurality
of aligned contacts of first and second electrical devices by merely placing
the sheet connector of this invention betw~en the contacts so that surface
contact is made between the contacts and the sheet In this invention
surface contact or touching need only be made to the sheet and compression
of the volume of the sheet betw~en opposing contacts is not necessary to achieveconduction, e.g. electrical contacts need on~y be screened on the sheet to
effect contacting.
This inven~ion is also directed to a new and improved homogeneous
material circuit board or sheet having a first circuit pattern element or
elements supported on one side thereof and making surface contact therethrough
to contacts or other isolated circuit patterns in surface contact with the
other side thereof where aligned with and opposed to portions of the first
circuit pattern element or elements.
The board or sheet of this invention comprises a binder e.g.~ plastic~
in which electrically conductive particles are homogeneously dispersed.
In the past, in order to make contact from elements on one side of
a circuit board to ele~ents on the other side of a circuit board, eyelets or
other material which extended from one surface of the board to the opposite
surface were provided.
The present invention does away with the requirement of such direct
connections in that the board of this invention has a low through resistance
between aligned and opposed contacts e.g., screen and inked or plated on
contacts adhering to opposite surfaces thereof.
At the sa~e time the sheet will permit isolated contacts positioned
on the same side of the board and in contact therewith to remain isolated from
each other when positioned an isolation distance apart from each other.
In this invention surface contact or touching need only be made to
-- 2 --
4~9
the board or sheet and compression of the volume of the board or sheet between -
opposing contacts to force electrically conductive particles together in the
sheet is not necessary to achieve conduction or lo~ through resistance, e.g.,
electrical contacts need only be screened on both sides of the sheet to effect
contacting from one side of the sheet to the other side of the sheet where
the circuit patterns are aligned and opposed.
The circuit board or sheet of the present invention can be termed
an isolated path circuit board in that it exhibits a lo~ through resistance
in a volume bet~een aligned opposing surface contacts on opposite sides of
the sheet and exhibits a higher isolation resistance in all volumes thereof
~t a distance greater than about the thickness of the sheet. Thus electrical
contacts e.g., circuit pattern portions positioned apart from each other on
the sa~e side of the sheet at a distance greater than about the thickness of
the sheet tan isolation distance apart) are electrically isolated from each
other even though another contact on the opposite sid~ of the sheet and
aligned with respect to one of said circuit pattern portions will be elect_
rically coupled through a l~w resistance portion of the board to said aligned
and opposed circuit pattern portions
In view of the foregoing mentioned properties of the sheet of this
invention it is now possible to make electrical contact between `a plurality
of aligned contacts of first and second d rcuit patterns adhered to the sheet
and in surface contact therewith or a plurality of elements of one circuit
pattern and the contacts of an electrical device positioned merely in surface
electrical contact with the opposite side of the sheet and in alignment with
elements of said one circuit pattern.
The connector of the invention in its preferred form in one aspect
comprises a layer or sheet of material comprising a binder and electrically
conductive particles. Upon application of contacts to surface points on
opposite sides of said material~ the resistance through volume between the
points is so low, e.g , less than 1000 ohms, preferably less than 100_200 ohms,
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78~7~
and most preferably less than 1 ohm, as to be useful for electrically coupl_
ing the points on opposite sides of said sheet to each other.
In addition, if added contacts are also applied as above to the
same material at second points closely adjacent the first mentioned points,
i.e., at a thickness greater than the thickness of the sheet (e.g., 5 times
the thickness of the sheet) the resistance between the first mentioned and
second mentioned points remains high, greater than 10 ohms, preferably great_
er than 107 ohms, and most preferably greater than 109 ohms such that the
first and second mentioned points are in effect electricaLly isolated from
each other
The invention in another aspect in its preferred form comprises a
board, layer or sheet of material comprising a homogeneous mixture of a
binder and electricaLLy conductive particles, said board supporting and in
electrical contact with a circuit pattern adhered to at least one side there_
of. Upon application of a first contact to the opposite side surface of the
board in alignment with a portion of the circuit pattern the through resist-
ance between the volume of the board between the aligned circuit pattern
portion and the first contact is so low, e,g., less than 1000 ohms, preferab_
ly less than 100-200 ohms and most preferably less than 1 ohm, as to be usefuL
for electricaLLy coupLing the circuit pattern portion to the contact.
In addition, if an added second contact is also applied as above
at the Qame time to the same materiaL at second poin~ closely adjacent the
first contact and out of register or aLignment wi~h the circuit pattern
portion i.e., at a thickcness greater than the thickness of the sheet e.g.,
5 times the thickness of the sheet, the resistance between the first mention-
ed and second mentioned contacts remains high, greater than 105 ohms, pre-
ferably greater than :L0 ohms, and most preferably greater than 109 ohms
such that the first and second contacts are in effect electrically isolated
from each other and tlle second contact is aLso electrically isolated from the
circuit pattern portion.
- 4 _
:~07~34~9
The thickness of the connector or circuit board, layer or sheet of
materic~l disclosed herein is preferably between 1 mil to 100 mils with a
thickness of 2 to 40 mils being preferred and a thickness of 10 to 30 mils
being most preferred. If the material becomes too thick, the material is no
longer economic. If the material becomes t:oo thin, then the material is hard
to handle since it does not have sufficient physical strength.
The present invention discloses the use of electrical conductive
powder or particles to produce the above mentioned electrical contacting
and isolating effect of the board.
As used herein the term electricAlly conductive powder or particles
is intended to include metal powders as well as metal coa~ed or covered
particles such as glass or ceramic or other conductive or insulator material
cores covered or coated with a layer of metal, or other electrically conduct_
ive particles such as titanium carbide.
The metals most desired for this invention includes the noble metals
such as sllver and gold or other metals such as copper and nickel or any
combination thereof such as silver coated copper.
In terms of volume per cent the conductive powder or particles
contclined in the board, layer or sheet of material should be less than 20
volume per cent to about .05 volume per cent with 9 to 18 volume per cent
being preferred where metal particles are used and .05 to ,11 volume per
cent being preferred where metal is covering an insulator core As used
herein the term volume per cent means volume of the sheet when considering
only the binder and the electrically conductive portion of the powder or part-
icles e.g., the metal coating the glass or the metal itself.
When coated particles are used the insulator core is to be added to
the binder for the volume per cent determination of the metal content, For
example, if the sheet contains binder equal to 70 volum~ per cent, and silver
coated glass cores are used, wherein the amount of silver in the sheet is .09
volume per cent and the core represents 29~91 volume per cent of the total
:
~137B47g
sheet, the amount of metal (silver~ is obviously equal to .09% volume per
cent of the total sheet, i.e., the sum of the binder, the glass cores and
the silver.
While various irregular shaped particles ma~ be uscd, for the
practice of this invention it is preferred that the particles be substantially
spheric~l in shape.
In addition, the particle si~e in terms of its maximum dimension
is preferably between .2 mils to 90 mils depending upon sheet thickness and
it is particularly preferred that the particle size is less than the thick-
ness of the layer or sheet of material so that the particIes do not extendabo~e or below the surfaces of the layer or sheet
For example, with sheet thickness of 20 mils it is preferred that
the particles be of a size of about 10 mils ~about 250 microns). It is also
highly desirable for the practice of this invention that the dispersity of
particle size should be kept to a minim~m with a variation of + 20 per cent
or less being preferred.
The binder materials suitable for the practice of this invention
include flexible insulator materials such as thermosetting plastics, ther_
moplastics and elastomers. As used herein the term plastic is intended to
include elastomers such as rubbers.
Examples of such materials include silicone rubber, ethylene
propylene polymer, Buna_N (nitrile rubber), polyurethane rubber, styrene but~
adiene rubber, natural rubber, neoprene rubber polyethylene, polypropylene,
vinyl chloride7 and acrylics e.g., polyethylmethylacrylate.
For the practice of this invention the sheet is preferably between
1 to 100 mils in thickness and more preferably between 2 to 40 mils in
thickness e.g., 6 mils.
In addition, the present invention does~ot preclude the use of
fillers, plasticizers, catal~sts, accelerators, pi~ments, smoothing agents
commonly utilized in conductive plastics or elastomers such as silica (useful
` 10~8479
for its mechanical binding properties) as long as these materials do not
severely affect the desireable properties of the connector.
It should be understood that the connector of this inv~ntion need
not be in sheet form and can take many other physical shapes e.g., wedge
shaped, step shaped or other molded forms as long as it operates in the manner
disclosed. For example, it may contain locating ridges, pTotrusions, etc.,
which make it particularly useful for a particular function. In addition, it
may vary in thickness over its length or other dimensions when desired.
The CiTCUit patterns of this invention may comprise conductive
coatings, inks or metal patterns (e.g., lines) which are direc~ly adhered
to the board surface or indirectly through electrically conductive adhesive.
The conductive inks or coatings may comprise plastics filled with
electrically conductive particles. The circuit patterns may be screened on,
printed or applied in any other conventional manner.
According to the invention there is provided an electrical one
piece connector in the form of a sheet having a thickness o~ between 1 to
100 mils and having top and bottom surfaces and which comprises a homogeneous
mixture of a flexible insulator material binder and electrically conductive
particles the maximum dimension of which is between 0.2 and 90 mils in an
amount of .05 to 20 volume per cent for providing at least when uncompressed
a low through resistance of less than 1,000 ohms between opposite aligned
points on said top and bottom surfaces as well as a high isolation resistance,
which is greater than 100,000 ohms, along the top and bottom surfaces between
points at a distance ~part equal to five times the thicXness of the connector
between said top and bottom surfaces further characterized in that the
connector exhibits said low through resistance through the volume between
aligned opposed electr;cal contacts placed on opposite top and bottom surfaces
thereof merely in surface contact therewith and said high isolation resistance
between diagonal electrical contacts placed on opposite top and bottom surfaces
thereof as well as between adjacent electrical contacts placed on the same
surface thereof all merely in sur~ace contact therewith at a distance apart
equal to five times the thickness of the connector between said top and bottom
~ 7
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surfaces.
According to another aspect of the invention there is provided a
coupling system comprising a sheet of plastic material having a thickness of
between 1 to 100 mils and having top and bottom surfaces, said sheet having
electrically conductive particles the maximum dimension of which is between
0.2 and 90 mils, homogeneously dispersed therethrough in an amount between
about 20 volume per cent to 0.05 volume peT cent for providing at least when
uncompressed a low electrical through resistance between opposite aligned
points on said top and bottom surfaces and a plurality of spaced apart
electrically conductive material elements supported by and adhered to and in
surface electrical contact with the same surface of said sheet, said conductive
elements being spaced apart on said surface of said sheet at least a distance
apaTt equal to about the thickness of the sheet so that they are electrically
isolated from each other by an isolation resistance greater than about 100,000
ohms.
The invention disclosed herein is shown in the preferred embodiments
of the drawings in a watch, calculator and for coupling electrical devices
together.
Figure 1 is a top view of a connector sheet or layer according to
the invention;
Figure 2 is a sectional view taken along line 2-2 in Figure l;
Figure 3 is a top view of the connector layer or sheet having a
portion cutout therein prior to placement into the structure shown in Figures
4-8;
Figure 4 illustrates the sheet of Figure 4 positioned between first
and second electrical devices such as a liquid crystal display and circuit
board;
Figure 5 illustrates a watch containing the connector as well as the
other members shown in Figure 4;
Figure 6 is a sectional view taken at line 6-6 in Figure 5 illus-
trating contacts being applied to the surface of the connector sheet;
; -7a-
~07847g
Figure 7 is an alternate embodiment for supporti.ng the connector
sheet in a watch or other device;
Figure 7A is a sectional view taken along line 7A-7A in Figure 7;
and
Figure 8 illustrates schematically the physical properties of the
connector of this disclosure.
Figure 9 is a top plan view of a sheet or board of this invention
used as a coupler and having circuit patterns adhered to both sides thereof;
Figure 10 is a sectional view taken along line 10-10 in Figure 10;
Figure 11 is a top plan view showing the coupling of an electrical
device to a board of this invention supporting a plurality of circuit patterns;
Figure 12 is a sectional view taken along line 12-12 in Figure 11;
Figure 13 is a bottom view of the board supporting the plurality of
circuit elements;
Figure 13A is a sectional view taken along line 14_14 in Figure 13;
Figure 14 is a top view of a keyboard using the circuit board of the
in~ention;
Figure 15 is a bottom view of the keys of the keyboard supporting
a circuit pattern adhered thereto and forming contacts;
Figure 16 is a bottom view of the board supporting a circuit
pattern used to generate a code;
Figure 17 is a sectional view taken along line 17-17 of Figure 16;
Figure 18 is a view similar to Figure 18 showing the key when
depressed;
Figure 19 is a top plan view of a digitcil watch utilizing the cir- .
cuit board of this invention;
Figure 20 is a sectional view taken along line 20-20 in Figure 19;
Figure 21 is a bottom view illustrating the circuit pattern slements
supported by the board;
Figure 22 is a botton view illustrating components of the watch
-- , ,
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847~
positioned on the board and coupled to the circuit pattern elements;
Figure 23 shows in a top plan view the bottom of the watch casing
supporting the components;
Figure 24 is a sectional view taken along line 24~24 of Figure 24;
and
Figure 25 illustrates in a botto~ view the display for the watch.
Figures 1 and 2 illustrate a layer, film or sheet of the connector
material 10 according to the invention and which in the configuration shown
may be placed between aligned contacts of two electrical devices to effect
electrical connection between aligned contacts while ~t the same time elect_
rically isolating adjacent electrical contacts of the same de~ice from each
other.
The sheet of connector material is preferabl~ of a thickness of 1
to 100 mils with a thickness of 10 to 30 mils being most preferred.
Thus with the connector sheet of this invention, ten to several
hundred or more aligned contacts may be made for ea~h square inch ~i.e., 1
sq. inch) of the material surface (top and bottom surface) as long as the
adjacent contacts are spaced apart from each other an isolation distance
greater than about the thickness of the sheet, i.e., the distance between
~o the top and bottom surfaces.
In a normal situation adjacent contacts of electrical devices used
with this invention will be spaced apart about 1 to 5 times the thickness of
the sheet and thus the connector sheet of this invention ~hen providing
electrical isolation at spacings equal to 1 to 5 times the thickness of the
sheet is usable in a wide range of applications.
It is most preferable that to insure isolation in practice that the
adjacent contacts be spaced at least about 1025 to 1.5 times the thickness of
the sheet.
The sheet of connector materials as stated before is preferably
flexible so as to conform to the plurality of contacts of the electrical dev-
~)'784L ~9
ices positioned upon it so as to insure good surface contact since quite of-
ten the elect.rical contacts of a device, e.g., circuit board, may be out of
alignment, i.e., in more than one plane.
The resistance between aligned contacts positioned on the opposite
surfaces such as shown in Figure 6, e.g., betueen contacts 15a and 16a will
depend for example upon the conductive particle loading, the thickness of
the sheet, the dimensions and shape of the conductive particles and the exact
binder.
In addition depending upon the ultimate use of the contacts9 the
contact resistance, i.e., between contacts 15a and 16a can in practice be
1000 ohms or less. For example, if a high input impedance device is being
interconnected a resistance of 1000 ohms per contact may be acceptable whereas
in cases involYing lower input impedance devices, contact resistance in the
order of 100-200 ohms per contact of less such as 1 ohm or less of contact
may be needed to effect optimum p~wer transfer.
Accordingl~v in its preferred form the resistance through the sheet
is preferabl~v less than 1000 ohms based on a measurement made with 25 mil
square contacts e.g. copper contacts and is more preferabl~ less than 200
ohms and most preferably 1 ohm or less.
-- 10 --
1()~78479
The resistance between ad~acent contacts e.g., 15a and 15b spaced
a distance Y apart as shown in Figure 6 and positioned in sur~ace contact
with the sheet is pre~erably at least 105 ohms or greater with isolation re-
sistances of 107 to 10 1 ohms or greater being pre~erred. Y in Figures 6 or
9 is a distance greater than the thickness X of the sheet.
In making the above isolation resistance and through contact resis-
tance measurements, an ohmeter such as the *Simpson 260 Series Ohmeter made
by the Simpson Electrical Company o~ Chicago, Illinois may be used, using ~5
mil square electrical contacting pads, e.g. of copper.
In Figure 3 there is shown a cutout 12 in the sheet connector so
that the connector 10 may be positioned as shown in Figures 4-6 in a watch
or other electrical system to couple contacts 15a-15~ o~ a ~irst electrical
device 15, e.g., a liquid crystal display to the contacts 16a-16~ o~ a second
electrical device 16 such as a circuit board supporting other circuitry not
shown e.g., on the underside thereo~.
The circuitry may comprise circuit patterns, passive devices, e.g.,
resistors, and active devices such as transistors to provide at contacts 16a-
*Trademark - 11 -
~C~7~479
16f, etc., the signals to drive the liquid crystal package via contacts 15a-
15f, etc.
It should be quite obvious to those skilled in the art that the
present invention is not limited to the interconnection of the contacts of
any specific or particular electrical devices and accordingly the in~ention
herein should be construed to cover the interconnection of any types of
electrical devices, e.g., circuit board to circuit board, integrated circuits
to circuits, etc, in which the invention disclosed herein could be utilized
by those skilled in the art. In addition the connector of this invention
may be used as a circuit board substrate and be used to support a circuit
which is to be interconnected to another circuit or a circuit board, or other
electrical device.
As may be seen in Figure 6 the contacts 15a and 15b are shown
aligned with contacts 16a and 16b. Surface contact is made ko the connector
sheet 10 by means of hold_down snap means 19 of the watch casing halves 17a
and 17b.
The closure of the wa~ch casing positions the aligned contacts3 e.g.,
15a and 16a into surfQce conforming contact with the connector sheet 10 there-
by electrically coupling contacts 15a to 16a, 15b to 16b and so forth while
electrically isolating contacts 15a from 15b, 16b from 16a, 15a from 16b and
16a from 15b which are at a laterial isolation distance Y apart from each
other. It may be observed that electrical continuity occurs between aligned
opposed contact pairs 15a a~d 16a while non-aligned opposed or diagonally
opposed contacts 15a and 16b are electrically isolated by a high resistance.
Therefore when current flows between contacts 15a and 16a it will
primarily flow in the connector material volume lOa and nDt be dissipated by
sloNing through different pathways to the non_aligned or isolated contacts 15b
or 16b.
In Figures 7 and 7A there is shown a plastic frame 20, eqg., of pol~_
prophylene for holding the connecter sheets 10 (in the form of strips) by ~ay
. .
:.,,, :. .
,.: : ' '
.
47~
of a slot 20a formed in the frame. The frame 20 may then be placed between
the electrical devices of Figure 4 to perform the same function as the
connector sheet having the cutout 12.
Figure 8 illustrates in schematic form the use of the connector of
the invention. In this Figure the connector is in the form of a sheet ha~ing
a thickness X e.g., 20 mils and the contacts A, B, C, D, etc., to be inter-
connected are shown on opposite sides of the sheet.
As may be seen contacts A and B are aligned at opposite sides of
the sheet surface to engage a volume lOa therebet~een and contacts C and D
are also aligned at opposite sides of the sheet surface to engage another
volume lOb of the sheet. The distance between contacts A and C, and B and D
along the surfaces of the sheet is set at a distance Y, e.g., 30 mils apart
although obviously this may vary.
Upon surface coupling of the contacts A or B~ or C or D, to the
sheet 10 (which may for example be a square contact having an area of .25 mils
by .75 mils, the resistance between contacts A to D or A to C is 10 to 10
ohms greater than the resistance between contacts A to B and the distance
bet~een contacts A and B is 1000 o~ms or less and is greater than zero ohms.
Thus the volu~e lOc between the contacts remains high in resistance
so as to effectively electrically isolate the contacts D or C from contacts
A or B. Upon the connection of contacts C and D between the * and - terminals
o~ a source (e,g., a battery) an indicator light shown at 23 may be illuminat~
ed.
Obviously in place of an indicator light other electrical devices
may be supplied with energ~ in a like manner.
Accordingly the present inven~ion provides an isolated pathway
connector or interconnector preferably in sheet form and which comprises a
fle~ible insulator binder having electrica~ y conductive particles dispersed
therethrough, said connector characterized in that it exhibits a resistance
of less than 1000 ohms between aligned electrical contacts positioned on
- 13 _
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~07~34~79
opposite sides ~top and bottom surfaces) of the sheet and making surface
contact therewith and a resistance greater than 105 ohms between diagonally
opposed contacts as well as contacts adjacent to each other on the same sur-
face of the sheet (top or bottom) at an isolation distance apart equal to 5
times the thickness of the sheet.
As used herein the term surface contact means that the electrical
contact comes into good electrical conforming contact with the sur~ace of the
sheet without necessarily ccnpressing the volume of the sheet between opposite
contacts to achieve low through resistance of the sheet volu~e between con_
tacts. For example the electrical contacts need onl~ be glued to the surface
or applied e.g., by screening thereto as an electrically conductive ink
The fol~owing examples illustrate the connector of the invention.
All ingredients in the examples unless otherwise specified are in terms of
volume percent
It should be understood that while-pressure is not necessary to
achieve the low through resistance as indiCated above the connector will
inherently operate when under pressure applied by two opposed contacts, e.g "
A and B.
~igures 9 and 10 illustrate the board or sheet of this invention
which has applied to it two circuit patterns. One circuit pattern 21 support-
ed on one side of the sheet c~mprises five lines or paths of conductive ink
spaced apart from each a distance of about two tim~s t~e thickness of the
sheet.
A second circuit pattern 24 is shown supported on the opposite side
of the sheet in the sam~ manner as the first circuit pattern.
As may be observed, portions at points a-e of each circuit pattern
are opposed to and in alignment with each other. Thus~ there is provided a
through path at points a_e between the circuit patterns 21 and 24 where they
are aligned.
On the other hand since each of the circuit pattern lines are
_ 14 -
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~78479
positioned a distance greater than about the thickness of the sheet apart,
they do not short out and are only coupled together where they are aligned
with each other.
Extended coupling of the circuit pattern 21 is accomplished via
connector 22 through pins 22_1 and external coupling of circuit pattern 24
is accomplished via connector 25 through pins 26,
Thus, the structure of Figures 9 and 10 provide a means for coupling
one electrical de~ice to another through the use of a board having circuit
patterns adhered to and suppor~ed on the opposi~e surfaces thereof. Current
will flow through each of the elements of the circuit pattern 21 through
the volume of the board and into the elements of circuit pattern 24 where
the elements of circuit pattern 24 are aligned on opposite board surfaces
with the elements or portions of circuit pattern 21 ~parts a-e).
No pressure need be applied to achieve a low through resistance
between the aligned elements of the circuit patterns and the diagonal or
adjacent positioned elements of each circuit pattern will remain isolated
from each other. Normally the isolation resistance be~ween elements of each
circuit pattern will be greater than about 10 ohms. This element 21a will
be isolated from adjacent elements 21b to e as well as from elements 24b to
c and elements 21a and 24a will be coupled together where they cross over~
Figures 11 to 13A disclose the use of the circuit board of this
invention coupling the contacts 31 of an electrical device 30 to electricall~
conductive circuit pat~ern elements 34 adhered ~o tke board 33. The elements
34 are connected to pins 36 supported in a holder 35, The assembly is held
together by supports 33 and an insulator plastic base m~mber 37 suppor~s the
circuit board as shown,
In Figures 14-18 there is shown a keyboard utilizing the in~ention~
The keyboard is shown at 39 and comprises a frame 40 supporting a top sheet
41 of resilient and flexible plastic e.g., Mylar in which snappable prot~usions
such as in United States Patent 3,860,771. The underside of the top sheet 41
~ ~rade /~ a ~l~
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10713479
is provided with an electricall~ conductive plastic coating 42 coupled together
via circuit lines 43 (as in United States Patent 3,860~771) coupled to pin
48-1 of pins 48-1 to 48-7. The pins 48_1 to 48-7 are supported in holder 47
of the same type as shown in Figure 13A.
The circuit board of this invention is shown at 44 and has on the
bottom thereof contact segments 45 which are coupled together or to pins 48-1
to 48-7 by circuit pattern elements 46, The circuit pattern elements and
the segments may be screened on and are e,g " of a thickness of about 2 mils
and the elements may be of a ~idth of about 80 mils with the segments being
about 150 mils to assure good connection with the depressible coating 42
when the finger depresses the protrusion 4 1 1 as shot~n in Figure 18, against
the top of the sheet in alignment and in opposition to the segments 45~
When the coating 42 makes surface contact between the top sur~ace
44-1 of the sheet, a low through resistance exists between segments 45 and
this conduction may take place be*ween common pin 48_1 and the other pins
48-2 to 48-7 depending upon trhich protrusion 41_1 is depressedO
Reference should now be had to Figures 19_25 which discloses yet
another structure for use in a watch of the digital typc to coupled components
such as integrated circuit chips~ batteries to a displa~ such a~ a liquid
crystal display.
In this figure the watch is shown at 50 and is coupled to a strap
52. The watch includes a top casing 51, e.g., plastic which snaps to a
botto~ casing 53, e.g., plastic in a conyentional manner.
A liquid crystal display iæ sho~n at 55 which includes a pluralit~
of oonductive pads 55-1 to 55-8 on both sides thereof as in United States
Patent 3,861,135.
The bottom casing 53 supports two integrated circuit cXips57 and
58 ~see Figure 25) which are to be coupled to the liquid cr~stal display pads
55_1 to 55_8. The integrated circuit chips include electricall~ conducti~e
pads 57-1 and 58_1 along the sides thereof, The battery is shown at 59 and
- 16 _
: ~0 784~9
includes a casing contact element 59-1 which provides one terminal and a
top terminal 59-2. The battery terminals 59-1 and 59-2 are coupled to chips
58 and 59 as shown through end pads 57-2 and 58_2 (see Figure 24). The
; chips 57, 58 and battery 59 are supported in wells 53_1 and are most preferably
urged upwardly by resilient biasing means, e.g., springs 53-2 to insure good
contact in the event of tolerance variation in the chips or batter~. A
resilient rubber pad can be used in place of the spring.
The display 55~ and integrated circuit chips (IC) 57 and 58 are
coupled together through circuit elements 56-1 to 8 supported on the bottom
1~ surface of the board 56 of this invention disclosure. The elements ma~ be
screened on as previously described.
Figure 22 discloses the ICts 57 and 58 and the battery 59 on top
of the bottom board 56 with the pads 57-1, 57_2, 58_1, 58-2, terminals 59-1
and 59-2 making contact with circuit elements 56_1 to 56-8 (on both sides of
the sheet) and circuit elements 56-2 to 56_3. In this manner direct contact
is made by the IC's and the battery 59 supplies pow~r to the IC's.
Contact is made to the contact pads 55_1 to 55_8 on both sides of
the display 55 through the board 56 where there is aligrn~ent between elements
561 to 56-8 and 55-1 to 55-8, where they are aligned as in Figure 21. It
should be understood that elements 55-1 to 55_8 align themselves with elements
56 1 to 56-8 on the circuit board 56
In this manner connection is made between the ICts and the display
through circuit pattern elements supported by and in surface contact with
the board 56 and the pads 55-1 to 55-8 in surface contact with the opposite
side of the board 56 as sho~n in Figure 20.
Reference should now be had-to examples which illustrate represent_
ative connector or circuit board c~mpositions, screening co~positions, and a
circuit pattern screen on a circuit board.
The foll~wing examples illustrate the connector of the invention.
All in~redients in the examples unless otherwise specified are in terms of
_ 1~ --
.: -
.
~07~47~ ~
volume per cent:-
EXAMPLE I
A connector as a sheet or circuit board is prepared from:
*Dow Corning 440 Silicone Gum Rubber - 79.ô3 vol. %
*Cabosil ~ 7 fumed Silica - 3.55 vol. %
*Chemalloy U.B. 20/325 grade - 15.70 vol. %
~ickel Powder (screened through 60 mesh,
caught on 100 mesh)-
Chemalloy ~o. Bryn 7 Mawr, PA
Varox Peroxide catalyst (50% active) - 0.92 vol. %
The rubber gum is banded together at room tempera-ture on a rubber
roll mill until a small bank is produced between the mill rolls. At this
time the Varox i8 added to the Silicone GlIm before it proceeds through the
rolls to force the Varox into the gum. In the same manner the silica is
added first and then the nickel is added. ~he gum uith the ~dded materiPls
is periodically cut as it comes out of the rolls and is re~ed through the
rolls until a homogeneous mixture is obtained. Fifteen passes have been
found to be sufficient.
The rolls of the mill are spaced apart to provide a sheet of about
25 mil thickness. The sheet is then placed in a compression mold at ~000 psi
pressure for 20 minutes at 325F to cure to provide a 20 mill sheet composed
of a homogeneous mixture of a flexible insulator material binder and elec-
trically conductive particles. The sheet is then post baked for 3 hours at
400 F to co~ple-te the cure.
The sheet thus obtained has a thickness of about 20 mils. Using
25 mil square contacts positioned as are contacts 15a and 16a in Fieure 6.
The resistance through the sheet was about 0.1 ohms when spaced along the
surface of the sheet 25 mils apart (as with contacts 15a and 16b in Figure
6) is greater than 107 ohms.
EXAMPLE II
-
The procedure of EXAMPLE I was followed except that Nickel Po~der
was screened through 100 mesh and caught on 325 mesh.
*Trademarks - 18 -
,, - - - ~ . .
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)78479
The sheet prepared was 20 mils thick. With the contacts aæ in
EXAMPLE I, spaced as in EXAMPLE I, the through resistance between aligned
opposed contscts was 2.2 ohms and the isolation resistance between ad~acent
contacts on the same side of the surface spaced apart 25 mils or similarly
diagonally spaced was greater than 107 ohms.
EXAMPLE III
The procedure of EXAMPLE I was followed except that the following
ingred~ents were used to form a 10 mils thick sheet under compression after
sheeting to 15 mils.
Dow Corning 440 Silicone Gum Rubber -80.03 vol.%
Cabosil MS 7 fumed Silica ~ 3.56 vol.%
Varox Peroxide catalyst (50% active) - 0.92 vol.%
Silver Plated Copper Powder as in
United States Patent No. 3,202,488
(7.66 vol.% AG) screened through 200 mesh -15.49 vol.%
Using aligned 25 mil square contacts the resistance through the
sheet was 0.7 ohms and when diagonally spaced apart 25 mils the isolation
resistance was greater than 107 ohms.
EXAMPLE IY
Using the mixing procedure of EXAMPLE I, except that the rolls are
heated to between 270F to 300F a 15 mil thick sheet connector was prepared
in a compression mold at 4000 psi for 3 minutes at 250 F and then cooling
same to 130F after sheeting to 20 mils with the following ingredients-
*Alathon 14 low density
*Polyethylene (Dupont) -47.98 vol.%
*Vistanex L 80 polyisobutylene
En~ay Chemical Co. -32.32 vol.%
Chemalloy Nickel of Example I -1,.70 vol.%
The through resistance between contacts for the sheet was .2 ohms
and the isolation diagonal contact resistance was greater than 107 ohms.
*Trademarks - 19 -
~07~3g7~
EXAMPLE V
. .
Following the procedure of EXAMPrE I a 20 mil thick sheet connector
or circuit board was prepared with the following ingredients;
Dow Corning 440 Silicone Gum Rubber - 71.27 volO%
Cabosil MS 7 fumed Silica ~ 3.17 vol.%
Verox Peroxide ~atalyst(50% active) - 0.82 vol.%
Silver Plated Glass Powder No. 24295 - 24.65 vol,%glass
(Potters Brothers, Carlstadt, New Jersey) - 0.09 vol.% Ag
The through resistance between contacts was 0.3 ohms and the
diagonal isolation resistance between contacts 15a and 16b was greater
than 10 ohmsO
EXAMFIE VI
The E~4MPLE I procedure and ingredients was followed except that
the volume percent o~ Nickel used was 18~74%o
The through resistance of the 20 mil thickness homogeneous sheet
connector was 0.05 ohms and the isolation diagonal and isolation adjacent
contact resistance at 25 mil spacing was greater than 107 ohms.
EXAMPIE VII
The EXAMPLE V procedure and ingredients ~ere followed except that
the volume percent of the glass was 14.69% and the volume percent of Silver
was 0.05%,
The through resistance between contacts was 8.5 ohms and the
isolation diagonal resistance at 25 mil spacing was greater than 10~ ohms
for the 20 mil thickness sheet.
EXAMPLE VIII
~ . .
Electri~all~ conductive Screening Ink
Parts b~ W~ _ %
General Electric _ Silicone RTV 615A 3.470
General ~lectric _ Silicone RTV 615B .340
General Electric _ Silicone RTV 815 - 12.850
_ 20 -
.. . .. .
1078~7~
Handy ~ Harmon Silver Powder P-135 - 78,130
Propylene Glycol ~ 5.210
100 %
The ingredients were mixed together in a conventional manner for
a liquid paste like substance ~hich is no~ suitable for screening on th0
boards or sheet of E~amples I to VII.
EXAMPLE IX
Electrically conductive Screening Ink
A polymeric mixture is prepared from 20 parts by weight of General
Electric SR_585 adhesive, 80 parts by weight silver plated copper powder
(granular) prepared in accordance with EXANPIE I of United States Patent
3,202,488 (average particle size 2_3 mils) and 30 parts of toluene.
EXAMPLE X
Screened on Circuit Pattern
The Ink of EXAMPCE VIII was screened on the sheet of ExAMpr~ II in
a conventional manner using a mask and a brush to forn the overlapping
circuit pattern 21 and 24 shown in Figures 9 and 10.
The lines on elements 21a-e and 24a_e are of a width of 80 mils
and are of a thickness of about 2 mils and the lines are spaced apart on the
same surface a distance of about 40 mils.
Other circuit pattern c~mpositions suitable for applica~ion to the
circuit boards may be prepared in accordance with the $xamples of United
States Patent, 3~576,387
