WO1998022987A2 - Laminated sheet product containing a printed battery - Google Patents

Abstract

A circuit in one embodiment of the present invention includes an integrated circuit (10) and a folded substrate (1). The folded substrate includes first and second circuit portions (5, 6). The first and second circuit portions are printed and aligned when the substrate is folded, to cooperate as a switch (13, 14) for providing an input signal to the integrated circuit. In a further variation, a fifth and sixth circuit portion are printed and aligned when the substrate is folded to cooperate as a speaker (11, 12) for vibrating a portion of the substrate at an audio frequency. In yet another variation, a piezoelectric element (34) is mounted on the substrate and coupled to the integrated circuit for vibrating a portion of the substrate at an audio frequency.

Description

LAMINATED SHEET PRODUCT CONTAINING A PRINTED BATTERY

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation in part application of, and claims priority from, U.S. Provisional Patent Application Serial No. 60/031,185 filed on November 19, 1996.

Field of the Invention

This invention relates to systems and methods for generating audible signals from a laminated sheet product containing a printed battery.

Background of the Invention

Laminated sheet products containing printed batteries and integrated circuits have been used, for example, in identification cards of the type described in U.S. Patent 5,055,968 to Nishi et al. In such cards, adhesives are used together with laminations made of plastic materials having thicknesses that together give the product a significant overall stiffness. Such a construction is inadequate for audio systems such as greeting cards or leaves of books due to the prohibitive cost of materials, the lack of flexibility of the completed product, and the lack of audio speaker and switch components that are compatible with manufacturing processes of such laminated products.

Thus, the need remains for systems and methods for generating audible signals from a durable, flexible, inexpensive, laminated sheet product containing a battery.

Summary of the Invention

Accordingly, a circuit in one embodiment of the present invention includes an integrated circuit and a folded substrate. The folded substrate includes first and second circuit portions. The first and second circuit portions are printed and aligned when the substrate is folded, to cooperate as a battery.

In a first variation a third and fourth circuit portion are printed and aligned when the substrate is folded to cooperate as a switch for providing an input signal to the integrated circuit. In a further variation, a fifth and sixth circuit portion are printed and aligned when the substrate is folded to cooperate as a speaker for vibrating a portion of the substrate at an audio frequency. In yet another variation, a piezoelectric element is mounted on the substrate and coupled to the integrated circuit for vibrating a portion of the substrate at an audio frequency.

Description of the Drawing

The subject matter of the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, may best be understood by reference to the following description taken in conjunction with the subjoined claims and the accompanying drawing of which:

FIG. 1 is representation of an exemplary environment, a greeting card with a sound feature, in which the present invention can be advantageously practiced;

FIG. 2 is shows the inner structure of the greeting card of FIG. 1 unfolded to particularly illustrate the wiring of the circuitry for the sound feature including a printed battery and a speaker;

FIG. 3A is a cross sectional view taken along the lines 3 - 3 of FIG. 1 and showing certain structure of a first embodiment of a printed battery;

FIG. 3B is a cross sectional view taken along the lines 3 - 3 of FIG. 1 and showing certain structure of a second embodiment of a printed battery; FIG. 4A is a cross sectional view taken along the lines 4 - 4 of FIG. 1 and showing certain structure of a first embodiment of a printed speaker;

FIG. 4B is a cross sectional view taken along the lines 4 - 4 of FIG. 1 and showing certain structure of a second embodiment of a printed speaker;

FIG. 4C is a cross sectional view taken along the lines 4 - 4 of FIG. 1 and showing certain structure of a third embodiment of a printed speaker;

FIG. 5 is plan view of a first embodiment of a printed speaker coil;

FIG. 6 is a plan view of a second embodiment of a printed speaker coil; and

FIG. 7 is a block diagram of an exemplary circuit for implementing the sound feature using the printed battery to energize an electronic circuit which selectively drives the printed speaker.

Description of the Preferred Embodiment(s)

Attention is first directed to FIG. 1 which illustrates a paper greeting card 1 (or a page from a multi-page paper greeting card) as an exemplary environment for practicing and explaining the invention. It will be understood, however, that the invention may be practiced in any suitable laminated sheet product.

Greeting card 1 is laminated with electronic circuitry (shown in dashed lines in FIG. 1) sandwiched between first and second outer layers, typically formed by suitably folding a single, prepared, larger sheet. The electronic circuitry, which includes the present invention, will be shown in further detail below. In that regard, attention is directed to section lines 3 - 3 and 4 - 4 which respectively relate to the layered structure of a printed battery and the layered structure of a printed speaker, each to be disclosed in detail below.

On the face of greeting card 1, in addition to the usual printed message, there are included, by way of example only, two marked positions 2 and 3 at which switches are provided in the electronic circuitry. Thus, a first message delivery function may be actuated by pressing the surface of greeting card 1 at marked position 2, and a second message delivery function may be actuated by pressing the surface of greeting card 1 in marked position 3. Actuating a given switch will result in audible delivery of the selected message which may be spoken and/or include musical content, sound effects, etc. As will become more evident below, other embodiments of the invention may include a plurality of such switches for actuating various functions.

Attention is now directed to FIG. 2 which illustrates both inner faces of laminated greeting card 1 and the layout of the electronic circuitry which achieves the selective audio feature of the card. As will become clear, left inner face 5 and right inner face 6 are preferably folded about imaginary central fold line 7 and glued in face-to-face relationship after the electronic circuitry is deposited, as will be described. While inner faces 5 and 6 could be sides of separate thin sheets, economies of production and technical advantages lead to the preference of using a single sheet to be processed and then folded into the laminated sheet structure.

The electronic circuitry has several components, and some of these components are completed when the folding step is carried out. In that manner, battery structure 8 on left inner face 5 integrates with battery structure 9 on right inner face 6 to effect a battery for powering integrated circuit 10. Similarly, audio speaker structure 11 on left inner face 5 integrates with speaker structure 12 on right inner face 6 to effect an operative speaker selectively driven by integrated circuit 10. Switch structure

13 and switch structure 14 integrate to effect the first message delivery switch, actuated at region 2 (FIG. 1). Switch structure 15 and switch structure 16 integrate to effect the second message delivery switch, actuated at region 3 (FIG. 1). The various electronic components are interconnected with printed conductors, and certain regions of inner faces 5 and 6 are overlaid with insulating layers to insure against short circuits, as will be described.

Battery structures 8 and 9, and speaker structures 11 and 12, are printed on inner faces 5 and 6 of example greeting card 1. Integrated circuit 10 is an off-the-shelf component, for example, model 50C14 or model 50C19, marketed by Texas Instruments, Inc. of Dallas, TX. Piezoelectric element 34 is an off-the-shelf component, for example, model 49PZ50100A-LA or 49PZ50100B-LA, marketed by DB Products, Ltd. of Hong Kong.

The following discussion of Figs. 3 A, 3B, 4A, 4B and 4C describe layered structures in which the thicknesses of the individual layers are very much exaggerated for clarity in illustrating and explaining their cooperative relationships. Those skilled in the art will understand that the thickness of each of these lamina in actual implementation is selected according to the application to provide completed battery and speaker components which are readily accommodated between a folded thin sheet

(or two thin sheets), then glued or otherwise fused to provide a laminated sheet containing electronic circuitry, having an overall thickness not inordinate for the intended purpose.

Reference may now be taken to FIG. 3 A, with reference to the lines 3 - 3 of FIG. 1, in addition to FIG 2, to reach an understanding of a first embodiment of the printed battery component of the electronic circuitry. When inner faces 5 and 6 of greeting card 1 are folded to complete the printed battery component, the laminated structure shown in FIG. 3A results. The manner in which the laminated structure is prepared before the folding step will be discussed below. To slightly simplify and clarify the presentation of FIG. 3A and other cross section FIGs. to follow, printed circuit leads are taken off to the right rather than in their actual positions as shown in FIG. 2, inasmuch as the placement of these leads is a routine function of individual printed circuit layout as well known in the art. In FIG. 3, inner faces 5 and 6 become, respectively, upper and lower substrates with the battery structure sandwiched therebetween. Lower electrically conductive pad 20 (for example, silver or copper) is printed on inner face 6. Similarly, upper electrically conductive pad 21 is printed on inner face 5. A printed negative supply lead 22 is taken off lower conductive pad 20, and a printed positive supply lead 23 is taken off upper conductive pad 21. Because of layout considerations in FIG. 2, two negative supply leads 22 are employed. A negative electrode 24 is printed on the inner surface of lower conductive pad

20, and a positive electrode 25 (not visible in FIG. 2) is printed on the inner surface of upper conductive pad 21.

A battery electrolyte and supporting and containing structure therefor, if desired, may be printed over either negative electrode 24 or positive electrode 25. In FIG. 2, electrolyte 26 and supporting structure 27 are shown printed on positive electrode 25 which is therefore out of view.

Electrolyte gel 26 is printed over positive electrode 25. For relatively large printed batteries, electrolyte gel 26 is preferably contained by printed support structure 27 which may, as shown in FIG. 2, advantageously divide the dielectric layer into several chambers for enhanced physical support and consequent reliability. A peripheral layer of adhesive 28 encompasses battery structure 8 to assure ongoing integrity of the battery formed when faces 5 and 6 are folded together.

It has been found that it is not necessary, for some electrode materials, to employ conductive pads 20, 21, shown in FIG. 3A, so that the simplified battery structure shown in FIG. 3B may be used instead. Referring to FIG. 3B, positive electrode 25 is printed directly on upper substrate 5 and connected to positive supply lead 23. Negative electrode 24 is printed directly on lower substrate 6 and is connected directly to negative supply lead 22. Conductive pads 20 and 21 may be eliminated when an electrode material: (a) will print directly to substrates 5 and 6 (typically, heavy paper); (b) will electrically and physically connect to printed leads 22 and 23; and (c) the electrode provides suitable physical strength. With some electrode combinations, it may be desirable to use a conductive pad with one electrode and not with the other electrode, resulting in a four-layer battery structure between substrates 5 and 6. Noted that for some relatively small batteries having a physically stable electrolyte gel, support structure 27 may be omitted (as in FIG. 3B) to further simplify the printed battery.

As shown in FIG. 2, the battery resulting from bringing together battery structures 8 and 9 is connected via printed conductors 22 and 23 to provide power to integrated circuit 10. In addition, negative leads 22 from the battery are supplied to one electrical side of each of the switch structures 13 and 15, whose operation will be described below.

Selection of materials for positive and negative electrodes and a suitable electrolyte is consistent with conventional primary battery technology with further requirements relevant to the printed nature of the electrodes and electrolyte in the present environment. For example, the positive and negative electrodes of dissimilar metals may be selected from the conventional oxidation/reduction table included in many physics and chemistry texts and handbooks, and a suitable electrolyte gel may be similarly selected. However, the electrode materials selected must each be amenable to being ground or otherwise rendered into small particles and mixed with a suitable liquid evaporable carrier to obtain a printable electrode "ink". The electrolyte should also be printable either in its normal state or mixed with a suitable liquid evaporable carrier. Further, the materials selected should be safe in the context of the intended application. For example, lithium, an energetic and commonly used battery electrode, should not be used in a greeting card environment without further treatment, for example, comprehensive encapsulation of the battery structure.

Electrodes in a first embodiment include a flexible polymer conductive ink containing silver for the negative electrode and a flexible polymer conductive ink containing nickel for the positive electrode. The ink includes resins for better adhesion to the substrate. Adhesion results in part due to absorption of the ink into the substrate. The thickness of each electrode is in the range 0.75 mil

(approximately 0.0190 millimeters) to 1.25 mil (approximately 0.0312 millimeter), preferably about 1.0 mil (approximately 0.0254 millimeter). For example, one variation employs ink containing silver of the type supplied by Acheson Colloids, Division, of Acheson Industries, Inc. Port Huron, MI as model SA725A. In another variation, ink containing silver is prepared from about minus 325 mesh powder in approximately a 2: 1 ratio by volume with resin of the type supplied by Acheson as model 6C52 or model 6C54. The powder is prepared containing silver and up to 30 percent by weight of carbon. Ink containing nickel is prepared from powder and resin, for example, in approximately a 2: 1 ratio by volume with resin. A resin of the type supplied by Acheson as model 6C52 or model 6C54 is used. The powder is prepared in one version containing nickel and carbon in approximately a 3:1 ratio by weight. Substrates 5 and 6 are preferably heavy paper in the thickness range of about 100 pounds (220 kilograms) per ream to about 10 point.

A battery structure preferred for low cost manufacturing includes 10 point paper, two identical layers of ink containing silver each about 0.75 mil (approximately 0.0190 millimeter) to form the negative electrode, a dielectric web, an electrolyte, and a positive electrode formed from two dissimilar layers, the first (applied to the paper) of ink containing silver and the second of ink containing nickel and carbon. The dielectric preferably includes vinyl or urethane in a gel or paste and is printed to form a web having several wells to contain electrolyte and improve durability. The web is about 1 mil (approximately 0.0254 millimeter) thick. A preferred electrolyte contains a wetting agent, thickener to retain the wetting agent, a weak base, and a binder. For example, in one variation, the electrolyte is 87% by volume wetting agent, 10% thickener (such as ethyl cellulose), 2% base (such as sodium hydroxide), and 1% adhesive binder (such as polymer resin). The wetting agent in one version is prepared as polypropylene glycol mixed one part by weight with nine parts water. In a variation the base is added to the remaining electrolyte mixture until the pH of the mixture is in the range 7.1 to 7.7, preferably 7.4. In an alternate variation, a weak acid is added in place of the weak base for a pH in the range 6.9 to 6.8, preferably 6.8. The configurations of FIGs. 3 A and 3B may be further modified by first laying down a thin layer of flexible, non-porous, insulating material, such as vinyl, over portions of inner faces 5 and 6 before the structures described above are deposited.

For some environments, use of a secondary, rechargeable battery may be desirable. A rechargeable printed battery is achieved by selecting appropriate electrodes and electrolyte, such as nickel and cadmium with known electrolyte, and providing suitable access to negative and positive leads

22 and 23 for hookup to a charging current source (not shown).

The speaker resulting from bringing speaker elements 11 and 12 together when inner faces 5 and 6 of greeting card 1 are brought together and glued may take several forms, for example: piezoelectric, permanent magnet and electromagnetic. Thus, referring to FIGs. 1, 2 and 4A, a first example of the cross section of the speaker structure identified by the lines 4 - 4 in FIG. 1 is shown. Upper conductive pad

30 is printed on inner face 5, and a corresponding lower conductive pad 31 is printed on inner face 6. Then, layer 32 of conductive adhesive is printed on upper conductive pad 30, and a corresponding layer 33 of conductive adhesive is printed on lower conductive pad 31. Finally, piezoelectric element 34 is laid over one of the layers 32 and 33 of conductive adhesive (shown over conductive layer 32 in FIG. 2) such that the piezoelectric speaker is completed when inner faces 5 and 6 are folded together and glued. Ring of adhesive 28 around the speaker structure serves both to insure the integrity and reliability of the assembled speaker and also to stiffen the paper in the region of the speaker which improves frequency response, clarity and intelligibility of the audibly reproduced message(s).

In the example, lower conductive pad 31 , and hence one side of piezoelectric element 34, via the conductive adhesive 33, is electrically connected directly to the negative lead 22 from the battery.

The upper conductive pad 30, and hence the other side of piezoelectric element 34 via conductive adhesive 32, is electrically connected to audio output lead 35 from integrated circuit 10. Thus, audio frequency signals from integrated circuit 10, which are referenced to the negative side of the battery, result in establishing corresponding movement of piezoelectric element 34 in the well known manner to obtain an audible signal. In this example, piezoelectric element 34 is not printed per se.

In an alternate variation, piezoelectric element 34 is formed by printing. In this construction, conductive pads 30 and 31 are printed with ink containing silver. A piezoelectric material, for example, a polyvinyldene fluoride (PVDF) material such as one of the type supplied by AMP, Inc. of Harrisburg, PA, is printed onto one of the conductive pads 30 and 31. A dielectric spacer may be printed partially under, over or both to insulate portions of the PVDF material from unintended electrical contacts. The

PVDF material is annealed with heat. The piezoelectric speaker is completed when inner faces 5 and 6 are aligned, folded together, and glued, bringing pads 30 and 31 into aligned contact with the PVDF material.

Consider now, with reference to FIG. 4B, a second, permanent magnet embodiment of the printed speaker. In this embodiment, permanent magnet 36 is printed on upper substrate 5, and printed coil 38 is printed on lower substrate 6, the two being electrically insulated from one another by printed insulation layer 37. Permanent magnet 36 establishes a magnetic field. Printed coil 38, driven by audio signals provided by integrated circuit 10 via output printed lead 35 with the return path through negative (ground) lead 22, responds to the audio signals by developing a coπespondingly varying electromagnetic field which reacts with the field of permanent magnet 36. Consequently, coil 38 and permanent magnet 36 move with respect to one another. The sheet material surrounding coil 38 and the sheet material surrounding permanent magnet 36 each acts as a speaker cone, further defined by the stiffening function of ring of adhesive 28.

Printed magnet 36 may consist of a mixture of neodiminium boron impregnated into a polymer slurry at a 600 grain mesh which is dried and subsequently magnetized. The third, electromagnetic, speaker embodiment shown in FIG. 4C is similar to that shown in

FIG.4B, but the reference magnetic field is obtained from a second coil rather than from a permanent magnet. In this embodiment, second coil 39 is printed on upper substrate 36 and is selectively (e.g., conventionally by a switch, not shown) energized directly (or in a conventional current limiting fashion utilizing a printed resistor, not shown) from the battery via printed conductors 22 and 23. Consequently, second coil 39 establishes the reference field for the varying field produced by coil 38 as previously discussed.

Printed coils 38 and 39, which are electrically separated by printed insulation layer 37, may take diverse configurations. For example, FIG. 5 shows spiral wound coil 70 which can be used as drive coil 38, field coil 39, or both in the electromagnetic speaker embodiment shown in FIG. 4C. Printed insulating area 71 serves to insulate line 22 to the center of spiral wound coil 70 from shorting out the windings. FIG. 6 shows fan shaped coil 72, driven at the edge and the center, which is particularly well suited for use as drive coil 38. In order to connect coupling conductor 35 to the center point of fan shaped coil 72, insulating pad 73 is printed before conductor 22 is laid down.

Referring again to FIG. 1 , as well as FIG. 2, the printed circuit includes upper switch (contact pad) regions 13 and 15 disposed on left inner face 5. Upper contact pad region 13 includes closely spaced, but not touching, conductors 41 and 42 which are, therefore, normally open. Upper contact pad region 15 includes closely spaced, but not touching, conductors 43 and 44 which are, therefore, normally open. A corresponding plurality of lower contact pad regions 14 and 16 are similarly provided on right inner face 6. Lower switch (contact pad) regions include, respectively, sets 45, 46 of parallel printed conductors. From an examination of FIG. 1 at switch regions 2 and 3, it will be understood that, when left inner face 5 and right inner face 6 are folded together along the fold line 7 during the greeting card fabrication process, upper switch structure 13 will register with lower switch structure 14 to provide a first switch. Consequently, conductors 41 and 42 are juxtaposed above and at right angles with respect to parallel conductors 45. However, they are held in normally spaced apart relationship by the thickness of a printed circumferential insulator ring 47. Therefore, the first switch is normally open, but pressing with a finger at the position indicated at 2 serves to locally deflect the sheet material inwardly and push conductors 41 and 42 into contact with transverse conductors 45 to thereby effect momentary closure of the first switch to initiate a function which has been assigned to the switch. The momentary closure of the first switch serves to momentarily place a circuit ground potential on input 49 to integrated circuit 10 to provide a first input signal to integrated circuit 10. Similarly, upper switch structure 15 registers with switch structure 16 to provide a second switch with conductors 43 and 44 juxtaposed above and at right angles with respect to parallel conductors 46. However, they are held in normally spaced apart relationship by the thickness of printed circumferential insulator ring 48. Therefore, the second switch is normally open, but pressing with a finger at the position indicated at 3 (FIG. 1) serves to push the conductors 43 and 44 into contact with the transverse conductors 46 to effect momentary closure of the second switch. The momentary closure of the second switch serves to momentarily place a circuit ground potential on input 50 to integrated circuit 10 to provide a second input signal to integrated circuit 10.

It will be apparent that as many such switches may be provided as may be desired or necessary for a given application. For a more detailed description of switches of this kind, one may refer to copending U.S. patent application Serial No. 08/554,734, filed November 7, 1995, entitled GAME

BOARD INCORPORATING APPARATUS FOR SELECTIVELY PROVIDING SENSORY GAME ENHANCEMENT AND METHOD FOR MAKING THE SAME by Stephen I. McTaggart, incorporated herein by reference.

Attention is now directed to FIG. 7 (as well as to FIG. 2) which includes a block diagram of an exemplary integrated circuit 10. Battery 60 is the battery completed by the integration of battery structure 8 and battery structure 9 previously described and in either of the embodiments respectively shown in FIGs. 3A and 3B or an equivalent. Similarly, speaker 61 is the speaker completed by the integration of speaker structure 11 and speaker structure 12, previously described, and in any of the embodiments shown in FIGs. 4A, 4B and 4C, or an equivalent. Switches 62 correspond to the switch pairs completed when the switch structures 13 and 14, and the switch structures 15 and 16 are integrated as previously described and such other switches as may be provided in a given application.

Switches 62 are coupled to microprocessor 63 which includes memory 64 in which one or more sequences of sounds are stored. Depending upon the identification of an active input signal, a predetermined audio drive signal sequence is sent to sound generator 65 which drives speaker 61 to render the selected audio passage/message signal audible. Those skilled in the art will understand that the memory for the storage of the sound passages may alternatively be incorporated in the sound generator. All components of integrated circuit 10 are available in a single off-the-shelf unit.

The purpose of output interface block 67 is to provide for the incorporation of visual and audible enhancements to the greeting card under the direction of microprocessor 63. For example, light emitting diodes (not shown) may be selectively energized by interface block 67 via output line(s) 68. For a more complete exposition of this optional feature, one may refer to U.S. Patent 5,484,292 for APPARATUS

FOR COMBINING AUDIO AND VISUAL INDICIA, filed November 24, 1992 by Stephen I. McTaggart, incorporated herein by reference.

Referring again to FIG. 2, it will be apparent to those skilled in the art that various insulating areas 55 must be laid down to insure against shorting out circuitry when the folding step is carried out to bring inner faces 5 and 6 together. For example, it will be observed that battery structure 9 has associated therewith three such insulating areas 55 which serve to prevent shorting the leads 22 and 23 to the opposite electrode structure. It will be clear to those skilled in the art that the positions at which such insulating areas are printed depends on the layout of individual circuits.

Printed or otherwise laid down adhesive layers 28 are provided in appropriate and available positions to obtain a stable folded, joined, or folded and joined structure. For example, in FIG. 2, adhesive is provided about the periphery of inner face 5 and also in various other regions available to obtain direct mating of inner faces 5 and 6.

While the materials and techniques which may be employed in practicing the invention are widely diverse, certain particulars of these materials and techniques as presently preferred will be found useful in readily fully understanding the invention. Any printing equipment that is capable of effecting selective solid coverage ink transfer distribution can be utilized to lay the conductive and dielectric deposits as required for a given layout.

Suitable printing equipment include Gravere and Flex-O-Press printing presses and screen printing apparatus. Standard multi-station offset printing presses can also be utilized, if properly configured to deposit the conductive traces in "solid coverage"; that is, so that the conductive ink deposited by the press printing units does not include any interstices. That is to say, in such a manner that the dots of conductive ink deposited by the press overlap or overlay to provide a continuous conductive path.

Specifically, web-fed offset printing presses typically include a number of successive print stations. Each print station is associated with a particular color, and, typically, includes upper and lower sets of rollers to selectively apply ink of that color to both sides of the web (i.e., foldable sheet 1) on a substantially concurrent basis. The web passes through the respective printing stations in sequence to develop a multi-color image. Each printing station applies its respective ink in accordance with an associated dot matrix (corresponding to a color separation) established by a plate. The operation of the individual units is coordinated so that the respective images as printed are in registry. The combinations of colors and relative dispositions of the matrices provide a composite image having the desired form, composition, and color.

Thus, for example, one set (e.g., the lower) of print rollers in the respective stations can be used to lay down the pictorial aspects and a second set (e.g., the upper) of print rollers can be used to deposit the various conductive, electrolyte, and insulating inks in a sequence optimized for a given circuit. Disposition of a continuous, sufficiently thick, conductive path along each conductive trace can be facilitated by employing a plurality of successive print stations, each applying a conductive ink in sequence. The respective dot matrices laid down by the successive units are preferably slightly offset, but overlap each other. The dots of ink, in effect, bleed together to ensure a continuous conductive path. This result can be facilitated by laying the conductive ink down more thickly than is typical for non conductive ink in a typical color process. A suitable flexible dielectric ink to use in insulating overlapping conductive traces from one another as described is the product marketed by Olin Hunt Specialty Products Inc., a subsidiary of the Olin Corporation of Ontario, California, under the name "37AC22 Curable Spacer".

The printable substrates 5 and 6 (which may be a single sheet as described) are preferably made of non-conductive material capable of accepting flexible conductive ink and the other inks used in printing the circuit, battery, and speaker. Any material is acceptable: (a) which will accept the inks employed, such as a heavy paper or suitably coated or otherwise prepared plastic, and (b) which can be folded without breakage. The material used may vary from pure paper to pure synthetic substances, including a variety of composite materials. For example, the products sold by Paper Sources International under the trademark "Chromolux" and by the Champion International Corporation under the trademark "Cromekote" consist of paper coated on both sides with a layer of synthetic material, available in overall thicknesses from approximately 6 to 18 thousands of an inch. The product marketed by the Kimberly-Clark Corporation under the trademark "Kimdura" consists entirely of synthetic paper, a polypropylene material, available in thicknesses ranging from about 3 to 12 thousands of an inch. The materials marketed by the Spring Hill Paper Company under the trademark "Claycoat" and by the ICI

Company of England under the trademark "Melinex" consist of a polyester substrate. These materials are all suitable to practice the invention and can all be folded for long-term durability in the manner described above. Thus, the term "paper" as used herein comprehends such materials as well as classical papers. Further, it is contemplated that a substrate having conductive properties may be employed by first coating the substrate surface or surfaces with the dielectric ink in at least those regions where conductive ink will be printed.

Suitable drying/curing steps are taken, as may be necessary, between some or all of the depositing steps, all as well known in the art.

Thus, while the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangements, proportions, the elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.

Claims

What is claimed is: 1. A battery powered circuit comprising: a. a paper substrate; b. a first circuit portion printed on the substrate and comprising a first metal; c. a second circuit portion printed on the substrate and comprising a second metal; d. an electrolyte layer printed on a circuit portion of the set consisting of first and the second circuit portions, the first and second circuit portions being aligned when the substrate is folded to form a battery; and e. an integrated circuit mounted on the substrate and coupled to the first and second circuit portions.

2. The circuit of Claim 1 further comprising: a. a third circuit portion printed on the substrate and coupled to the integrated circuit; and b. a fourth circuit portion printed on the substrate and aligned, when the substrate is folded, to cooperate with the third circuit portion as a switch for providing an input signal to the integrated circuit.

3. The circuit of Claim 1 further comprising a piezoelectric element coupled to the integrated circuit and mounted to vibrate a portion of the substrate at an audio frequency.

4. The circuit of Claim 1 further comprising: a. a magnet printed on the substrate; and b. a third circuit portion printed on the substrate, forming a coil, the third circuit portion being aligned with the magnet to vibrate a portion of the substrate at an audio frequency.

5. The circuit of Claim 1 further comprising: a. a third circuit portion printed on the substrate, forming a first coil, and coupled to the integrated circuit; and b. a fourth circuit portion printed on the substrate, forming a second coil, the fourth circuit portion being aligned with the third circuit portion to vibrate a portion of the substrate at an audio frequency.

6. The circuit of Claim 5 wherein the portion of the substrate for being vibrated is defined by a printed ring of adhesive.

7. The circuit of Claim 1 wherein a non-porous layer, printed on the substrate underlies a portion of the first circuit portion.

8. The circuit of Claim 1 wherein the first circuit portion comprises silver and the second circuit portion comprises nickel.

9. The circuit of Claim 1 further comprising a dielectric material printed on a circuit portion of the set consisting of the first and second circuit portions.

10. The circuit of Claim 9 wherein the dielectric layer defines chambers for receiving electrolyte of the electrolyte layer.