CA1071319A

CA1071319A - Support having electrically conductive tracks

Info

Publication number: CA1071319A
Application number: CA281,114A
Authority: CA
Inventors: Cornelis J. Hendrikx
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1976-06-29
Filing date: 1977-06-22
Publication date: 1980-02-05
Also published as: FR2357145A1; JPS533657A; BE856160A; IT1080953B; GB1528889A; ES460125A1; FR2357145B3; DE2727301A1

Abstract

ABSTRACT:
A support having a pattern of electrically conductive tracks to which support a current con-ductor is secured which is in electrical contact with a track of the pattern. The conductor is locally sunk at least partly in the surface of the support and is enclosed by the support material.

Description

~(97 9L3~L~3 The invention relates to a support having a pattern of electrically conductive traeks, to which support ;s secured a current conductor of an electrical element wh~ch is in electrical con-tact with a track of the pattern. Such a support is disclosed in United States Patent Speciflcation 39894,236.
The known support is used in a flash bulb unit having several flash bulbs. The current conductors of the bulbs are slid in metal lead-through sleeves each provided in an aperture in the support and are secured by bending, a bent edge of the sleeve making the electrical contact wi~h a track of the circuit. Thus an extra com-ponent is necessary to connect the current con-ductors to the support and the circui~ prov1ded thereon. This is a drawback. For the connection of a current conductor several operations are necessary in which in addition the introduction o~ a leadthrough sleeve in the support and the insertion of a current conductor in the sleeve .. . .
requires an accurate alignment of the two com-; ponents. These operations result in a long assembly time. ~;
It is the object~of the invention to provide a support of the kind mentioned ln the - :: :'~'.
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preamble to which the current conductor ~s secured in a simple and rapid manner, without the use of an extra connection component, and in electrical con-tact with a track of the pattern.
For that purpose the support according to the invention is character~zed ~n that in a~ least two placed the current conductor 1s sunk at least partly in the surface of the suppor~ and is enclosed by the support material, between which connection places the current conductor is in electrical con- ~`
tact with the track of the pattern. The current con-ductor is situated between the connection places on or above the support surface and presses against the track.
If the connection places are present on either side of the trackg they will preferably be chosen near the edge of the track so that the cur-rent conductor forms an electrical contact with the edge of the track. Under the influence of the clamp-; 20 ing effect of the part of the current conductor situated between the connection places, the edge of the track is deformed to form a groove at the area of the conductor, and the electr~cal contact place ; ls enlarged. According as the material of the current conductor is stiffer, the distance between the mechanical connection place and the electrical contact place may be chosen to be larger.
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The support may consist of a thermoplastic synthetic resin, for example polystyrene, polymetha-crylate or a partly cured thermocuring synthetic resin, which still becomes plastic upon heating.
The electrically conductlve tracks may be proYided on the surface of the support by means of silk screening, transfer-printing or another tech-nique, for example the electrolytic covering, the electroless cover1ng, or the local etching away of a conductive layer, and may be ~ormed from a metal, for example silver, nickel, tin or other readily conductive materials, for example graphite. The thickness of the track generally is between lO and lOO microns.
lS In order to increase the distance between the tracks, the support sur~ace may be provided with grooves and/or ridges extending between the tracks.
The support according to the invention may be used in lamp unit having one or more flash bulbs or glow lamps, and in c~rcu~t arrangements in wh~ch electrical components, such as resistors and . ~ . , .
glow light starters with associated capacitors are incorporated.
Generally~ a contact resistance lying .
between 0.1 Ohm, for example in the case of silver tracks, and a few tens~of an ohm, ~or example, in the case of nickel tracks, is realised between the .~; ~ ', ~ , :': ~ ;' ~ .
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current conductor and ~he electr~cal track, this also dependent upon the exten~ to which the con-ductor presses against the track.
In connection with ~he softening temp-erature o~ the support material the maximum per-miss~ble curren~ strength through the conductor will be approximately l Ampere.
The inven~on is part~cularly suitable ~or current conductors having a diameter bet~een 0.2 and 0.8 mm. As materials are used metals, for example nickel, copper molybdenum, tungsten and alloys, ~or example fernlco.
An advantage of the support according ; to the invention is that the mechanical connection o~ the current conductor in the support material and the electrlcal connect~on of the current con- -ductor to a track of the pattern are effected in one operational step. MoreQver, the positioning .
of the current conductor w~th respect to the sup-port may be dane with a greater tolerance than ~n the known supports.
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Another advantage of the support is that in the manu~acture there may be started from a supportlng member wh~ch does not have spec~al provisions at the connection places as is the case in the known support. This contrlbutes ~o a cheaper produce.

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The current conductor may be secured to the support in an ultra-sonic operation. There is started from a current conductor wh1ch is laid on the support surface in such manner that it lies on the track of the pattern to be connected. In the connection place the conductor is made to vibrate ultra-sonically by means of a sonotrode. In said ~;
place the ultrason~cally vibrating conductor trans-fers energy to the support of synthetic material which is softened at that area, after which the current conductor is pressed in the plastically deformable material. Ihe materiai is pushed aside by the conductor~and stowed at the circum~erence of ;~
the conductor~ After embedding of the current con-l:5 ductor, the material solidifles and the current conductor ~s locked in the support material and in clamping contact with the track. Instead of the current conductor,-it is alternatively possible to give the support an ultrasonic vibration.
According to another method of securing ~;
in which a support of impact-resistant polystyrene, for example butadlene-styrene copolymer and acrylo-nitrile burad~ene-styrene plastic is preferably used, the current conductor, after providlng same across the track to be connected on the support, is pressed in the cold condition in one or a few , ~
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place. The support material is pushed aside by the current conductor and is stowed at the circum-ference of the conductor. After termination of the processing operation the current conductor is em-bedded in the support material and in clamping con-tact w~th the track.
Although German Patent Specificatlon

2,007,266 discloses a vibration device for connect-ing a wire to a printed circuit, the connection pro-duced in said specif~cation is a welded jo~nt be-tween the wire and a track of the circuit. Such a connection ~mposes spec~al requirements upon the ~aterial and the thickness of the track and the wire. The invention on the contrary uses no weld- ~ -ing process and hence no fusion of metals occurs.
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As a result of this the choice of the materials and the thickness of the track is much less criti-:.
cal. `
; ~ It is to be noted that a plastics support is known from 6erman Offenlegungsschrlft 2,121,465 wh~ch is provided w~th an electric wiring of cir-cular wire on which electrical conductors are soldered. The wiring is provided in ducts recessed in the support surface which are locally squeezed so as to hold the wlring.
A preferred embodiment oF the sùpport is characterlzed in that at least one of the connection ', ,:
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3i~L9 places is situated within the boundary of the track.
In this embodiment the current conductor is forced through the track in a connection place. In said place the track has lost its coherence. The width of the track at the connection place is preferably taken to be larger than the thickness of the con-ductor so that the track continues uninterruptedly on at least one side of the conductor.
In this embodlment of the support the electrical contact place directly adjoins the ;~
mechanical connection place. The formed contact has a very favourable contact resistance since the cur-rent conductor reg~dly engages the track.
According to another embod~ment of the support both connection places may be situated within the boundary of the track. Each connection place now has an electrical contact area having a very favourable ; contact resistance, between whlch connection places the conductor has a curved variation. ;
The invention also relates to a ~lash bulb unit having a support according to the invention.
The invention w~ll be described in greater detail with reference to the drawing, ~n which Fig. 1 is a perspective front elevation -, .
of the support accord~ng to the invention, Fig. 2 is a sectional view o~ an enlarged ;

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scale of a first embodlment of the connection of a current conductor to the support taken on the line II - II of the support shown ~n Fig. 1, Fig. 3 ~s a sectlona1 view of the detail shown in F;g. 2 taken on the line III - III. .
Fig. 4 is a sectional vlew on an enlarged scale of a second embodiment of the connection of a current conductor to the support taken on the line IV - IV of the support shown in Fig 1, Fig. 5 ~s a sectional view of the detail shown in Fig. 4 taken on the llne V - V~ and Flgure 6 shows a flahs-bulb un~t having a support as shown in Fig. 1.
The support 10 shown in Fig. 1 has a print-ed electr~cal circuit of which parts of the n~ckel tracks 11 and 21 are v~sible. rhe track thickness is 20 microns. A high-voltage flash-bulb 12 is situated on the support and is connected to the support 10 by means of the current conductors 13 and 23 and makes an electrical contact with the tracks 11 and 21 of the circuit. The ignit~on voltage of the flash bulb 12 is 1000 vo1ts. The current conductors consist of Fernico and have a diameter of 0.4 mm.
F~gs. 2 and 3 show on an enlarged scale a detall of the connection of the current conductor 13 to the support 10 of polystyrene. The conductor . ' .
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13 crosses the ~rack 11 and, on either side of ~he track 11, is sunk in the support material at the places 14 and 15, which material tightly encloses the conductor 13.
The cunrent conductor 13 has been secured to the support by means of a sonotrode, not shown, having a vibration frequency of 20 KHz. When the conductor 13 is forced into the support material at the connection places 14 :
and 15, said material is slightly pushed aside and is stowed on either side of the conductor 13 so that raised portions 16 and 17 are formed. Said raised portions con-tribute to a good mechanical connectlon o~ the conductor.
The loop-like part of the conductor 13 between the places .-.
: 14 and 15 makes an electrical clamping contact with the ~.
track 11. The edge llA of the track adjoining the con--~ 15 nection place 14 ~s deformed at that area under the :~
in~luence of the clamp~ng effect of the conductor 13.
- Figs. 4 and 5 show on an enlarged scale the . .
connectiQn of the current conductor 23 to the support .:-.. 10 of impact resistant polystyrene. The conductor 23 20; extends parallel to the track 21 and is forced through the track 21 ~n two places 24 and 25 and is enclosed in ;.
the support material.
The current conductor 23 is forced in the support material ln the cold sta~e by means of a pin, 25: not shown, having a diameter of 1.5 mm, w~th a force ~ "
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~97~1L3~L9 of 200N. During the pressing operat~on, the raised portions 26 and 27 have been formed ~n the connection places 24 and 25 and closely surround ~he conductor 23. The conductor electrically contacts at least the parts of the track 21 adjoin~ng the connection places 24 and 25. Notablyg the conductor 23 is in a very good contact w;th the edges 21A of the track 21 situated in the places 24 and 25.
Figure 6 shows a flash bulb unlt accord-ing to the invent~on hav~ng a support as shown in ; Fig, 1. The support which is referenced 30 consists of polystyrene and has a th~ckness oF 1.5 mm. Refer-ence numerals 31, 32, 33 and 34 denote high voltage . .
flash bulbs which are mechanically connected to the support 30 by means of the current conductors 35 and are connected electrically to the tracks ~f the c~rcu~t 36 printed on the support, all this in a manner as shown in F~g. 2, 3, 4 or 5. The support 30 is enclosed in a plastlcs hnus~ng 37 wh~ch is closed ' 20 by a transparent co~er overlying the flash bulbs.
A reflector member 39 is s~tuated between the flash bulbs and the support 30. The Flash bulb unit in th~s embodiment has two cannection members 40 and 41 which can be placed in a fitting aperture of a photo camera. The circuit 36 printed on the support .

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is such that the flash bulbs 31 and 32 can be fired - when the un~t is coupled to a camera by means of the connection member 40, and the flash bu1bs 33 and 34 can be fired when the unit is coupled to a camera by means of the connection member 41.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS

1. A support having a pattern of electrically conductive tracks to which support a current conductor of an electrical element is secured which is in electrical contact with a track of the pattern, characterized in that in two places the current conductor is sunk at least partly in the surface of the support and is enclosed by the support mater-ial, between which connection places the current conductor is in electrical contact with the track of the pattern.

2. A support as claimed in Claim 1, characterized in that at least one of the connection places is positioned within the boundary of the track.

3. A support as claimed in Claim 1, characterized in that both connection places are positioned within the boundary of the track.

4. A flash bulb unit having a support as claimed in any of the preceding Claims.