SE452925B - STAND-FREE SWITCHING DEVICE - Google Patents

Description

15 20 25 30 35 40 452 925 2 adjustable resistor or converter. But this paper relies on volume resistance, ie. the resistance through a relatively thick volume of the molybdenum disulfide layer. The present invention, on the other hand, utilizes the contact or surface resistance of a very thin layer of molybdenum disulfide. More specifically, U.S. Patent No. 3,806,471 discloses a molybdenum disulfide volume (thickness) of 0.0254 to 25.4 mm using molybdenum disulfide particles in the order of 50-600 mesh to provide a high but finite number of three-dimensionally distributed current paths through the resistive material. During compression, the number of current paths between the particles in the volume increases, causing the resistance to decrease. The semiconductor layer, on the other hand, is placed permanently and placed between two conductive electrodes.

In addition to the functional features described above, the structures disclosed in this cited U.S. patent require that the semiconductor volume be placed between two conductors or between a conductor and an insulating plate in close contact with either the insulating plate or conductors. Such an assembly is fundamentally different from the present invention, where the semiconductor material layer must necessarily have at least one contact surface which is not in close contact with either a conductor or another semiconductor layer. Such an arrangement utilizes the physical contact resistance over the surface of the material instead of the surface resistance of the individual particles through the volume of the material as in the cited patent specification 3,806. & 71.

The present invention utilizes particle sizes on the order of 1 μm and bearing thicknesses which are preferably less than D, 025h mm. Furthermore, since the variable resistance occurs due to a larger or smaller number of surface contact points, a surface of the semiconductor layer must either initially be separated from one of the conductive electrodes or be in close contact with the opposite surface. Pressing the conductive electrode against the surface of the thin semiconductor layer results in several contact points being obtained along the surface. These contact points increase as pressure is applied, thereby reducing the resistance between the conductive plates or contacts on either side of the semiconductor layer. The semiconductor layer may be any suitable particulate semiconductor material which is held together and secured to the surface by adhesive.

A significant advantage of the thin semiconductor layer according to the present invention is that the semiconducting material used to form the layer can be combined with an adhesive and a thinner for the adhesive, after which it is sprayed or fabric printed on the desired surface to form a layer with a thickness as small as 1 mm or less.

Labor and material costs can thus be greatly reduced. In addition to the above-mentioned advantages, the use of molybdenum disulfide to cover the conductive layer effectively protects the surface of the conductor from contact with air. This alleviates the serious problem that arises with the use of conductors that slowly corrode when exposed to air.

The present invention also substantially eliminates the electrical vibrations inherent in most switches. Thus, the resulting switching unit is free of bounces.

U.S. Pat. No. 4,044,642 discloses a touch sensitive resistor for use in musical instruments. However, the device utilizes a semiconductor material that is placed between two conductive plates in a manner similar to that of patents 2,375,278 and 3,386,067. In particular, according to U.S. Pat. No. 4,044,642, a resilient material such as foamed rubber or a foamed synthetic polymeric material is used, in which a particulate material such as graphite is distributed. The switch has a foamed semiconducting layer and an insulating layer with an opening thereby placed between two conductive plates. Thus, when a compressive force is applied, the graphite-saturated, resilient foam layer is deformed into the opening in the insulating material to initially provide electrical contact to thereby connect the musical instrument. Then, further depressing force causes the resistance between the two conductive plates to decrease in a manner previously described.

It is therefore desirable to provide analog conversion devices which do not depend on the suspension of the semiconductor layer and which further do not depend on the volume resistance through a relatively thick semiconductor layer.

According to the present invention, there is provided a bounce-free switch apparatus having a boundary layer resistance or surface contact resistance which varies inversely with a pressure applied vertically thereto, comprising a first conductive part, a pressure sensitive bearing and a second conductive part. The invention is characterized in that the pressure-sensitive layer comprises a semiconducting material, which is arranged to cover the first conductive part with intimate electrically conductive contact therewith, which pressure-sensitive layer has a first surface with a plurality of microscopic projections of semiconductive material, which extends from the first surface to provide a plurality of surface contact points, and that the second conductive member is located in a substantially non-electrically conductive relationship to the pressure sensitive bearing, whereby the bounce-free switch apparatus is normally open. The bounce-free switching apparatus is closed in response to a compressive force applied to force the second conductive member and the first surface together to increase the physical contact between the microscopic protrusions and the second conductor, thereby enabling electrical conduction through the affected microscopic protrusions. wherein the electrical conductivity increases as the value of the compressive force increases and decreases as the value of the compressive force decreases.

A second embodiment of the invention comprises two pressure-sensitive layers which can be correspondingly brought into contact with each other to vary the surface contact resistance between them.

Full understanding of the present invention and the above-mentioned advantages is obtained by the following description of preferred embodiments with simultaneous reference to the accompanying drawings in which: Fig. 1 is a cross-sectional view of an embodiment of a pressure-sensitive, analog switch with the pressure-sensitive coating placed between two conductor plates spaced apart; Fig. 2 is a side view taken in cross section of a bounce-free switch apparatus in accordance with the invention; Fig. 3 shows a curve where the pressure is plotted against the stress and which curve shows the variations in voltage across the semiconducting material layers as compressive forces which compress these two layers increase; Fig. 4 shows a graph giving the output voltage of the bounce-free switch in accordance with the invention as shown in Fig. 5; Fig. 5 shows an embodiment of a bounce-free switch apparatus in accordance with the invention which has only one semiconductive material layer; Fig. 6 is a view, partly in pictorial form, partly in schematic diagrammatic form, showing a double, lateral conversion switch disassembled in accordance with the present invention in an unfolded, open manner; Fig. 7 is a cross-sectional view taken from the side of the switching apparatus of Fig. 6 taken along line 7-7; Fig. B is a partly car-like, partly schematic view showing in disassembly another embodiment of the double, lateral switch according to the invention; Fig. 9 is a partially schematic, partially cut-away perspective view showing a string switch in accordance with the invention; Fig. 10 is a cut-away plan view from the side of a dual-function, touch switch according to the invention; Fig. 11 is a cross-sectional side view showing an embodiment of a pressure transducer according to the invention broken away; Fig. 12 is a plan view taken from above of the flexible base portion of Fig. 11 in the folded position, which view shows the conductive pattern applied to this portion; Fig. 13 is a side cross-sectional view of a second embodiment of the pressure transducer according to the invention taken, the top of the flexible base being constituted by a flap arranged to be moved laterally around a hinge part; Fig. 14 is a plan view taken from above of the flexible base of Fig. 13 in an unfolded position, showing the conductive pattern applied thereto; Fig. 15 is a simplified, partial cross-sectional view, partially schematic, of a musical instrument comprising a pressure transducer, as shown in Figs. 11-13; Fig. 16 is a plan view taken from above of the flexible base of Fig. 13 in an unfolded position, which view shows a further wiring pattern.

Referring first to Fig. 1, there is shown an analog switch according to the present invention comprising a first conductive plate 50 which is spaced from a second conductive plate 52 by means of the separating members 54 to define a gap or space 60 therebetween. first and second conductive plates 50 and 52, respectively. At least one of the conductive plates 50 or 52 is resilient so that it can be pressed down against the second conductive plate to close the switch.

The conductive plate may comprise a flexible carrier layer 64, such as e.g. mylar, with a thin conductive layer 66 of silver or other conductive material sprayed, printed or otherwise applied to the surface of the backing layer 64 adjacent the second conductive plate 52. The second conductive plate 52 may comprise a rigid plate base portion 68 with a thin copper surface 70 applied thereto. Of course, the base portion 68 may also be flexible and the thin surface 70 may be of silver or some other suitable conductive material. A lead wire 56 and a lead wire 58 may be connected to the silver layer 66 and the copper surface 70, respectively, to allow electrical connection of the analog switch to a utilization circuit.

Finally, a thin semiconductor layer 62 of semiconductor material is sprayed, pressed or evenly applied otherwise to the copper surface 70. Alternatively, the semiconductor material 62 may be sprayed, printed or otherwise applied evenly to the conductive layer 66 or to both the copper layer 70 and the conductive stored 66.

The semiconducting material may be of any suitable compound which is sprayable, printable, or otherwise has a consistency which allows it to be evenly applied to form a smooth exposed surface. For example. For example, the semiconducting material may be particulate molybdenum disulfide having particle sizes on the order of 1-10 / M mixed with a binder such as resin to form a liquid. A resin thinner may be added to give the composition a suitable consistency for spraying. The thin semiconductor layer 62 of the semiconductor material is then sprayed or printed on the conductive layer 66 by the carrier layer 64 or on the copper surface 70 of the rigid base portion 68. Of course, the semiconductive layer may be of any thickness provided there is an exposed, smooth semiconducting surface.

However, in order to save semiconductor materials and to minimize the surface irregularities that may occur, the thick semiconductor layers are used, a thickness of the order of about 0.0254 nm or less is preferred.

The spacer portion 54 may have different appearances. For example. in a particular embodiment shown in Fig. 1, the spacer portion 54 is simply an extension of the backing layer 64, wherein the backing layer has been folded over all or a portion of the periphery of the useful portion of the conductive member. the bearing 66. The fold 20 acts as a spring which seeks to maintain the distance from an external compressive force or an external pressure.

Thus, the fold not only constitutes a means for maintaining a distance but it also gives the part 50 an elasticity which substantially increases the sensitivity of the transducer.

It will be appreciated that the arrangement in Fig. 1 is illustrative only. Thus, the semiconductor layer 62 may be applied to one or both of the support layers 68 or 64 or be located directly on the support layer 66 to act as a shunt between the conductors 56 and 58 when the conductor 58 is located on the support layer 68 in a lateral relationship spaced from the conductor. 56.

Referring to FIG. 2 shows a further embodiment of the invention for providing a bounce-free switch which has a surface contact resistance which varies inversely with the pressure normally applied thereto. In particular, a bounce-free switching device 100 has a first support member 102 which may be made of mylar, a rigid plastic material or any other suitable non-conductive base material. A first conductor 104 is applied to the surface of the support member 102 with a first pressure sensitive material layer 106 placed thereon to cover and be in close contact with the conductor member 104.

Placed adjacent usually to the first pressure sensitive material layer 106 is a unit comprising a support member 110, which may be of mylar, rigid plastic or some other suitable non-conductive material, a conductive member 111 applied to one surface of the support member 110 and a second, pressure sensitive material layer ll4 applied to cover and stand in close, electrically conductive contact with the conductor ll2. The unit comprising the second support 110, the second conductive part 112 and the second, pressure-sensitive material layer 114 is located opposite the unit comprising the first part 102 to the first conductive part 104 and the first, pressure-sensitive material layer 106 so that the exposed surface l08 of the first, pressure-sensitive material layer l06 is in non-intimate but touching contact with the exposed surface ll6 of the second, pressure-sensitive material layer ll4 to thereby define a non-intimate contact connection l18. The first and second, pressure sensitive material layers are made of a particulate, semiconducting material, with particle sizes preferably in the order of 1-10; ¿, although larger sizes are possible.

The particulate semiconductor material is then mixed with a binder material and, if necessary, a thinner diluent, after which it is sprayed, screen printed or otherwise applied to conductors 104 and 112, respectively. Thus, each resulting pressure sensitive material layer 104 and 114 has a plurality of particles extending outwardly from the surface mean plane of the respective pressure sensitive material layers 106 and 114 and forming microscopic protrusions of particulate semiconducting material. It is these microscopic protrusions that allow the first and second pressure sensitive material layers to touch without therefore being in intimate electrical contact. But when a pressure is applied and compresses the two surfaces against each other, the microscopic protrusions on the respective pressure-sensitive material layers are pressed down against each other and form more and more electrical contact points, whereby the resistance across the connection 118 decreases. However, since there are already a small number of contact points with electrical contact (although these are extremely few and result in a very high resistance when the respective pressure-sensitive material layers are not pressed against the other), the vibrations which are then obtained are virtually eliminated. mechanical contacts are brought into contact with each other in conventional switches. Furthermore, all vibrations that can be generated occur only when the resistance across the connection 118 is extremely high, whereby the voltage drop across the connection 118 is also high, which means that the relative voltage deviation or variation is very small.

During operation, a pressure is applied to compress the respective pressure-sensitive material layers against the other so that the resistance across the connection 11 decreases as the number of contact points between the microscopic protrusions of the particulate semiconducting material increases, causing the voltage drop across the connection to decrease. This in turn gives an increase in output voltage at l28 as shown in Fig. 3. By coupling this voltage to the threshold circuit l22, a bounce-free transition from the ON-TO position at the output 130 can be obtained as generally shown in Fig. 4.

Of course, a threshold circuit is not necessary in many types of circuits, especially those that use different types of CMOS circuits, which have inherent limitation.

An alternative embodiment of the invention according to which only one of the conductors has a pressure-sensitive material layer placed thereon is shown in Fig. 5. In particular, a conductive part 132 is mounted on top of an insulating support part 13 with a pressure-sensitive material layer 134 applied to cover the conductor 132 and be in close electrical contact with it. A second conductive part 138 is similarly mounted on a second support part 14. The second conductor 138 is then placed in non-intimate, but touching, contact with the exposed surface 136 of the pressure sensitive material layer 134. In a manner similar to that previously described, the small microscopic protrusions of semiconductor material allow the conductor 138 to be in touching, but non-intimate, and substantially non-conductive contact with the semiconducting layer 132, resulting in an extremely high bonding resistance between the conductor 138 and the surface 136 of the pressure sensitive material layer. Although different particle sizes and bearing thicknesses are possible in accordance with the invention, it has been found that there is an inverse relationship between the amount of electrical vibration caused at the closing or opening of the switching contacts and the size of the molybdenum disulfide particles. Thus, the finer the grain size of molybdenum disulfide, the smoother the transition from the OFF position to 10 15 20 25 30 35 40 452 925 s ON position (or vice versa). In particular, it has been found that particle sizes smaller than 1 μ, and preferably about 0.7 / 2, provide a substantially vibration-free switching transition.

Another embodiment of the invention comprises a new switching apparatus, which essentially functions as a double-pole, single-disconnecting switch, wherein two independent switches are activated simultaneously, i.e. closed in response to a simple transverse force. At least one of the switches may be so pressure sensitive that the amount of voltage drop across the switch varies inversely with the amount of touch pressure applied to the switch.

Referring to Figs. 6 and 7, the pressure-activated dual switching device 210 has a support member 212 which may be of a flexible, resilient material such as a thin layer of mylar. The support part 212 has a first or bottom part 214 and a second or top part 216. The first part 214 and the second part 216 of the support part are delimited by a folding line 218, along which the second part 216 is folded over, but at a distance from the first part 214.

A plurality of conductors are located on one side of the support member 212. In particular, a first conductor 220, electrically connected to the first tin terminal 222, is mounted on the surface of the support member 212 in a first pattern 224. A second conductor 230, electrically connected to a second terminal 232, is mounted on top of the support member 212 in a second pattern 234. The first pattern 224 and the second pattern 234 of the first conductor 220 and the second conductor 230, respectively, are mounted on the first portion 214 of the support member 212.

A third conductor 240 is electrically connected to the third terminal 242 and mounted on the second portion 216 of the support portion 212 in a conductive pattern 244, which constitutes the reciprocal image or mirror image of the first conductive pattern 224. Finally, a fourth conductor 250 is electrically connected with the fourth terminal 252. The fourth conductor 250 is mounted over the first part 214 and on the second part 216 of the support part 212. The fourth conductor 250 is placed on the second part 216 of the support part 212 in a pattern 254, which is the equivalent of, i.e. the mirror image of the second pattern 234.

A semiconductor assembly 260 is mounted on top of at least one of the first, second, third or fourth conductors. Of course, it will be appreciated that the semiconductor assembly 260 may be mounted on top of several of the conductors. Thus, electrical contact is obtained through the bearing of the semiconductor assembly.

This effectively provides a contact resistor between the conductors 220 and 240 so that a resistor is in series with the switch defined by the conductors 220 and 240. The layer of the semiconductor assembly 260 may be of any suitable material which is sprayable, printable or otherwise has a consistency that allows it to be applied evenly to form a smooth exposed surface covering the conductor as previously described. A double pressure actuated switch may be formed by folding the support member 212 along the fold line 218 so that the second member 216 is aligned with the first member 214 and the pattern members of the first conductor 220 and the third conductor 240 is aligned transversely and the pattern portions of the second conductor 230 and the fourth conductor 250 are also aligned transversely. The first and third conductors comprise the contacts of one switch and the second and fourth conductors comprise the contacts of the second switch.

A spacer 262 is placed around the conductors between the first part and the second part so that the first and the third conductors 220 and 240, respectively, and the second and fourth conductors 230 and 250, respectively, can normally be kept at a distance from each other. In addition, it will be appreciated that the first and second conductors 220 and 230, respectively, and on the first portion 214 and the third and fourth conductors 240 and 250, respectively, on the second portion 216 must be laterally close to each other to allow a simple transverse force to cause the first and the third conductor 220 and 240, respectively, and the second and fourth conductors 230 and 250, respectively, to be simultaneously displaced into an electrically conductive relationship.

The switching device may be used in an electrical circuit having a first and a second utilization circuit 264 and 266. The utilization circuits 264 and 266 may have any suitable circuit configuration, such as e.g. those described in U.S. Pat. Nos. 3,609,203 and 3,796,756.

It will be appreciated that the patterns formed by the conductors on the support member may have any configuration provided that the conductors of the respective two switches are close enough together to allow simultaneous activation through the finger of an operator.

In addition, the support part can be made in two sections with the first and third terminals mounted on the first support part and the second and fourth terminals attached to the second support part. Referring to Fig. 8, a further embodiment of the invention is shown comprising a first base member 270, which may be of flexible mylar material, a rigid plastic material or other suitable non-conductive material, and a second base or support member 272 in transverse relationship to , spaced from the first base portion 270. A first conductor 274 is mounted on the surface of the first base portion 270.

The conductor 274 includes a first contact portion 276 with a plurality of interdigitating fingers 278 and a second contact portion 280 also having a plurality of interdigitating fingers 282. The first contact portion 276 is electrically connected to a first terminal 284 and the second contact portion 280 is electrically connected to a second terminal 286, a first utilization circuit 288 may then be electrically connected between the first terminal 284 and the second terminal 286 in a manner previously described in connection with the embodiment of Fig. 6. A second conductor 290 is similarly attached to the surface of the terminal 286. first base portion 270. The second conductor 290 has a pattern which in one embodiment is a U-shaped pattern 10 15 25 30 35 40 452 925 10 ster arranged around the first conductor 274. As in the previous embodiment, the first the conductor 274 and the second conductor 290 are located laterally, spaced apart on the first base portion so close together that a simple touching transverse force will simultaneously a activate the switches which respectively comprise the first conductor 274 and the second conductor 290.

A third conductor 292 is similarly mounted on a surface of the second base portion 272 opposite along the first conductor 274 and a fourth conductor 294 is mounted on the same surface of the second base portion 272 opposite in line with the second conductor 290. Thus, the first conductor 274 and the third conductor 292 comprise the contacts of a first switch and the second conductor 290 and the fourth conductor 294 comprise the contacts of a second switch according to the present invention.

In the preferred embodiment, the third conductor 292 is simply an electrically insulated conductive portion on the second base portion 272 and has a size sufficient to overlie or cover the entire first conductor 274. The fourth conductor 294 has a size and shape corresponding to the second conductor 290. The first, second, third and fourth conductors 274, 290, 292 and 294, respectively, may be of any suitable material and may e.g. be a thin layer of sprayed silver, a thin layer of copper or other suitable conductive material.

In order to obtain a variable contact resistance, a semiconductor assembly 296, substantially similar to that previously described, may be applied to receive the FIRST conductor 274, the third conductor 292 or on one or both of the second and fourth conductors 290. respectively 294.

In yet another alternative embodiment, the layer of the semiconductor assembly 296 may be omitted and the third provided conductor 292 may be made exclusively of the semiconductor material. In such an embodiment, a separate conductive layer such as e.g. the silver or copper layer previously described, is provided for the third conductor 292.

Finally, a second utilization circuit 298 may be connected between the second conductor 290 and the fourth conductor 294.

An advantage of this last embodiment is that a plurality of similar dual switching devices can be arranged in the form of a keyboard, whereby every fourth contact of each separate dual switch can be combined in a common local contact arrangement, whereby the number of electrical contacts which must be closed for to authenticate the majority of double switches in the keyboard is minimized.

Referring to Fig. 9, a partially cut-away view of another new multiple touch switch in accordance with the invention is shown. This switch is particularly useful for generating a string in response to the application of a simple, touching transverse force. The multiple touch switch 30 functionally comprises a plurality of individually electrically isolated switches grouped in groups g, 10 15 20 25 30 35 40 * iïciííl uuALnv 11 452 925 m of fabric or more. Each such group constitutes a string switch. A plurality of string switches are arranged side by side to form a keyboard with the multiple touch switch apparatus 3010.

In particular, the multiple touch switch apparatus 30 comprises a first support layer 320 which may be of a rigid, insulating plastic material or may be of a resiliently deformable material such as mylar. A plurality of conductive multi-segment bearings 322, each representing a separate string switch, comprise four first 7 electrically insulated conductors, e.g. the conductors 324, 326, 328 and 330, each representing a pillar or contact of the individually electrically insulated switches 325, 327, 329 and 33T, respectively, are then mounted on or otherwise fixed to the top surface 332 of the first support layer 320. In the embodiment of the invention in which a string can be generated upon application by a simple transverse force, the plurality of first electrically insulated conductors 324, 326, 328 and 330 are located laterally. close enough to each other that when an operator's finger is pressed against the multiple touch switch apparatus 30, contact can be made with the top surfaces of the plurality of first electrically insulated conductors 324, 326, 328 and 330 to thereby simultaneously close all electrically insulated switches 325, 327, 329 and 331 to generate a string.

Although each of the first electrically insulated conductors 324, 326, 328 and 330 may be a single layer made of a purely conductive material, such as a layer of silver, copper or some other similar conductive material, preferred embodiment each of the first, electrically insulated conductors of two layers; a conductive layer attached to the top of the first support layer 320 and a first semiconductive material layer that is sprayed, fabric printed, electrostatically plated, vacuum deposited or otherwise applied to form a very thin layer of a semiconducting material covering the entire conductive layer. stored.

In one example, according to the preferred embodiment, the first electrically insulated conductor 324 comprises a first conductive layer 334 on top of which a first semiconductive material layer 336 is applied by spraying, screen printing, or by another suitable method.

Each of the first electrically insulated conductors 324, 326, 328 and 330 is laterally separated from each other to provide the necessary electrical insulation.

Insulating spacers are not used between the first, electrically insulated conductors, which comprise a simple string switch so that a smooth transition between one string and another, which has either additional tones or excluded, can be achieved without buttoning - by simply rolling the operator's finger along the surface of the touch switch 3010 to close or break the contact with one or more of the first, electrically insulated conductors. On the other hand, an insulating, transverse spacer is provided to surround each multi-segment conductive layer 322, 452 925 112, i.e. each string switch. ï.ex. in the embodiment according to Fig. 9, a plurality of units of individually electrically insulated switches, one for each string to be generated, is mounted on the top surface 332, each such unit of electrically insulated switches being surrounded by a transverse spacer 338. _ / _ v §_ ~ __ The_multiplace touch apparatus 310 further comprises a second support layer MK lz44 medsen_bottom surface 340 to which a uniform conductive layer 342, common to all string switches, is attached. The integral conductive layer 342 may be a copper or silver layer, which is preferably applied by plating, spraying, electrostatic plating, or by any other suitable technique by which a thin conductive layer may be attached. the bottom surface 340 of the second carrier layer * 344ï * “rïÅ ,, _ \\ _ \ _ * _ -._ f Preferably, although not necessarily, a second semiconducting material layer 346 is attached by spraying, cloth printing, or otherwise at the exposed surface of the uniform conductive layer 342. The resulting structure comprising the second support layer 344, the uniform conductive layer 342 and the semiconductive material layer 346 is then secured by gluing, by any suitable mechanical fastener or to any another way to the transverse spacer 338 so that the semiconducting material layer 346 is located adjacent to, transverse to and spaced from the semiconducting material layers of the string switches. the bearing 344, the unitary conductive bearing 342 and the semiconducting material layer 346 are resiliently deformable so that when an operator presses his finger against the multiple touch switch apparatus 310, the second support bearing 344 is resiliently deformed to force the semiconductive material layer 346 into electrical contact with one or more of the semiconductor material layers of one of the several units of the first, electrically insulated conductors, such as conductors 324, 326, 328 and 330.

Thus, it will be appreciated that each of the electrically insulated switches, such as switches 325, 327, 329 and 33] which represent a string switch perform a separate switching function, but that all or a selected number of these switches may be closed in response to the application of simple concerning transverse force.

To illustrate the connection of the switching device 310 in Fig. 8, a voltage control oscillator (SPO) 350, which generates a simple high frequency signal, coupled to a peak voltage generator 352, is well known in the art, which e.g. includes frequency divider circuits for generating a plurality of output signals, each of which has a different frequency, on one of the plurality of outputs. In order to generate a string using the above-mentioned multiple touch switch devices 310, it is only necessary to select four tones and then identify the particular frequency of these music tones. The discharge from the peak octet generator 352 having this frequency is then connected to one of the first conductive layers of the first 40, electrically insulated conductors 324, 326, 328 or 330. Similarly, 10 15 is 25 25 25 35 40 13 452 925 ' the remaining first conductive layers of the first electrically insulated conductors are connected to the appropriate lead from the peak current generator 352 which has an output signal with the remaining selected frequencies. Thus, when a transverse touch force is applied to the multiple touch switch apparatus 310, the semiconductor material layer 346 will be pressed into contact with one or more of the semiconductive material layers by the first electrically insulated conductors 324, 326, 328 or 330 to thus coupling one or more signals, each with a different frequency, to the unitary conductive layer 342 where these signals are combined and output to an amplifier 354 and then made audible by means of the speaker 356.

In a preferred embodiment of the invention, the first, electrically insulated conductor 324 has its conductive layer 334 coupled to the frequency output of the peak octet generator 352 which has the frequency of the bass tone of the string. In addition, to allow the bass tone of the string to be played alone more easily, the first electrically conductive conductor 324 is made wider than the rest of the first electrically conductive conductors 326, 328 and 330.

From the above description it thus appears that if the operator wishes to play a string with four tones of different frequency, it is only necessary to apply a simple touching transverse force at a place which causes the first semiconductor layer 346 to come into contact with each of the first, electrically insulated conductors 324, 326, 328 and 330. If the operator wishes to exclude a tone from the string, it is only necessary for the operator to roll his finger slightly to thereby open one or more of the individually electrically insulated switches by disconnecting the associated transverse force.

The multiple touch switch device 3010 can also be designed with a simple PA / AV switch, which is stacked in a laminate-like manner to the previously described keyboard arrangement. For example. in Fig. 9, a first PA / AV switch conductor 360 is mounted on the top surface of the second support layer 344 and a second PA / AV switch conductor 362 is located over the bottom surface of a third support layer 364 to face the first PA / AV switch conductor 360. The first ON / OFF switch conductor 360 and the second ON / OFF switch conductor 362 are then spaced apart in a conventional open switch mode by means of a spacer 366, which can t. ex. comprise a strip of rectangular cross-section attached between the second support layer 344 and the third support layer 364.

The PAIAV switch can be connected between a voltage source 36l and the SPO and the peak-voltage generator. So if the keyboard is not pressed to shut down at least one of the string switches, no power will come to the SPO or via the peak coke generator. In another embodiment of the invention, each multi-segment lead layer 322 in Fig. 9 comprises a single, electrically adjacent conductor instead of four electrically. , _._., _-., ......_...... ,. . . , -.................--. l0 15 20 '25 30 35 40 452 925 14 isolated conductors. In such an arrangement, a touch-sensitive single-note keyboard may be provided by connecting each electrically adjacent conductor to a secondly sequential frequency output from a peak generator, such as the peak generator 352 of Fig. 9: Referring to Fig. 10, a touch switch arrangement includes with dual function in accordance with the invention a first support member 620 made of an insulating material which may be flexible or rigid. The first support member 620 carries a top surface 622 on which a first conductive layer 624 is applied.

A second support member 626, also made of an insulating material, is spaced from and above the first support member 620 by means of the spacers 628. A second conductive layer 630 is located or otherwise attached to the bottom surface of the second the support member 626 opposite but separate from the first conductive bearing 624. The second support member 626 is made of a material that is resiliently deformable so that the second conductive bearing 630 can be pressed down into contact with the first conductive bearing 624 by the application of a transverse force F.

Thus, the movement of the second conductive layer 630 in contact with the first conductive layer in response to an applied transverse force provides a first touch switch 632.

A second touch switch 642 which can also be activated in response to the same transverse force F is incorporated by providing a third conductive bearing 634 on the top surface of the second support member 626. A third support member, which is also made of a resilient, deformable material, is spaced above the third conductive layer 634 by means of second spacers 640. A fourth conductive layer 638 is attached to the bottom surface of a third supporting layer 636 opposite but spaced from the third conductive layer 634 in a conventional open, i.e. non-conductive relationship. The third support member 636 and thus the fourth conductive bearing 638 are spaced from the third conductive bearing 634 by the second spacers 640.

In operation, the application of the transverse force F, which can be applied by ordinary depression against the top surface of the third support member 636, causes the third support member 636 and the fourth conductive bearing 638 to resiliently deform into electrical contact with the third conductive bearing 634 to thereby stop. the second switch 642, which is connected between a power source 643 and the power supply input of a utilization circuit 644. If additional transverse force F is applied, the second support part and thus also the third conductive bearing 34 and the second conductive bearing 630 are resiliently deformed so that the second conductive the bearing 630 is brought into electrical contact with the first conductive bearing 624 to thereby close the first switch 632 and thereby connect an input signal to the utilization circuit 644.

In a basic embodiment of the present invention, each of the First, Second, Third and Fourth Conductive Bearings 624, 630, 634 and 638, respectively, simply comprises a conductive layer or conductive plate applied to a suitable first, 10 15 20 25 30 35 40 15 452 925 second or third support members 620, 626 and 636.

In an alternative embodiment, at least one of the first or second conductive bearings 624 and 630 comprises a conductive bearing on top of which a layer of semiconducting material is applied to thereby connect a resistor in series with the switch. Similarly, the second conductive layer 630 may include a second conductive layer 650 covered by a second semiconducting material layer 652.

Of course, one or both of the third and fourth conductive bearings 634 and 638 may also include a semiconductor top surface bearing to provide an additional variable resistance across the switch 642. Although the switches 632 and 642 of the present dual-function touch switch apparatus, which previously described, concludes substantially at the same time that it is realized that in reality there is a very small delay between the time when the fourth conductive layer 638 contacts the third conductive layer 634 and the time when the second conductive layer 630 contacts the first conductive layer 624.

This very small delay allows current to be connected to the utilization circuit 644 before the input signal is applied to the utilization circuit 644. This allows the various circuit components to be fully supplied with power and thus operable before the connection of the input signal.

It will be appreciated that more than two switches may be stacked on top of each other in a single, touch switch apparatus to thereby provide a multi-function touch switch apparatus, without thereby departing from the inventive concept. Each such additional touch switch device may be designed as previously described.

Another embodiment of the present invention is shown in Fig. 11, which illustrates a pressure transducer device 410, which has a rigid base part 412, a weighted, flexible base part 414 with a lower part 416 and an upper part 418, a diaphragm spacer 422, a resilient , deformable diaphragm 424 and a stop ring 426.

Referring more particularly to Fig. 12, the flexible base portion 414 is shown in an unfolded arrangement with a connecting portion 428 extending from the lower circular portion 416, which is attached to the circular, reciprocally formed, upper portion 414 through a bridge. or hinge region 434. A first conductor 436 is mounted on the flexible base base portion 414 to extend from the connecting portion 428 and to define a contact pad 440 at a central portion of the lower portion 416. A second conductor 438 is likewise mounted on the flexible base 414 beginning at the connecting portion 428 and extending in a semicircular path around the periphery of the lower portion 416 over the hinge or bridge portion 434 and terminating at a central location in the upper portion 418. to thereby define a contact pad 442. The first conductor 435 and the second conductor 438 are electrically insulated from each other along the surface of the flexible base portion 414. The contact pads 440 and 442 and the upper and lower portions 4116 and 418 may Be of any desired shape. But both the contact pad 440 and the contact pad 442 must have such a shape and be placed on the lower part 416 and the upper part 418 that when the upper part 418 is folded along a folding line 444, the contact pad 442 will be transversely aligned with the contact pad 440 to allow electrical conduction between the contact pad 440 and the contact pad 442 when the upper portion 418 is forced against the lower portion 416.

In order to obtain variations in the voltage drop between the first conductor 436 and the second conductor 438 in response to variations in the pressure with which the upper part 418 is pressed into contact with the lower part 416, a first semiconducting material layer 446 is applied by spraying or otherwise to cover the first conductor 436 including the circular contact pad 440. Similarly, though not substantially, a semiconductive material layer 448 is also applied by spraying or the like to cover the second conductor 238, particularly including the contact pad 442.

The semiconductor material is preferably a mixture of molybdenum disulfide, a resin and possibly powdered carbon, which is diluted with a resin diluent to obtain sprayable consistency. Thus, a very thin layer of the semiconducting material layer can be applied to the top of the first and second conductors.

Referring to Fig. 11, the flexible base member, which may be made of thin (preferably on the order of 1/2 to 5 mm) of mylar, is folded into a sandwich-like arrangement with the float-shaped spacer 420 therebetween.

An adhesive material is then applied to the top and bottom surfaces of the spacer 420 with the lower portion 416 and the upper portion 418 held by the semiconductor material covered contact pads 440 and 442 opposite but spaced therefrom. The bottom surface 428 of the lower part 416 of the flexible base is also glued to the surface 450 of the rigid base part 412. Thus, the lower part 416 of the flexible base 414 is retained in a rigid state by the rigid base 412, while the upper part 418 of the flexible base 414 is transversely movable in contact with the lower part 416.

In the embodiments shown in Figs. 11 and 12, the spacer 420 is positioned to adhesively connect the lower portion 416 and the upper portion 418 of the flexible base 414 around the entire periphery or at least a substantial portion of the periphery of the two portions 416. and 418. In one embodiment, the spacer may simply be a double-sided adhesive tape cut into a suitable shape.

An aeration hole 429 may also be provided between the chamber defined by the spacer 420 and the region outside the transducer 410.

The resilient, deformable diaphragm 424 is then adhesively attached to the top surface of the diaphragm spacer 422, which is adhesively attached to the upper portion 418 of the flexible base portion. The spacer 422 may be a toroidal coil-shaped or float ring-shaped portion with a square or rectangular cross-section 10 15 20 25 35 17 452 925 and may also be cut from double-sided tape. Thus, the peripheral edges of the resilient, deformable diaphragm 424 are spaced from the upper portion 418 and the flexible base portion 414. However, to ensure that the upper portion 418 continuously responds to both increasing and decreasing compressive forces, a central portion of the resilient member is deformable diaphragm 424 on the sides and spaced from the edges of diaphragm spacer 422 adhesively attached to the top of the upper portion 418 of the flexible base portion 414. Thus, as increased pressure is applied to the diaphragm 424, the upper portion 418 will be pressed downward until the semiconductor material covering contact pad 442 is in electrical contact with the semiconductor material covering contact pad 440. The greater the force exerted on the upper part 418 the smaller the contact resistance between the upper and lower contact pads 442 and 440 and thus also the voltage pressure across the first and the second conductor 436 and 438 nonetheless. As the compressive force decreases, the inherent suspension in the diaphragm 424 decreases, which e.g. may be made of a stretchable rubber such as dust rubber, to pull the upper portion 418 in a direction away from the lower portion 416 to thereby increase the contact distance between the lower contact pad 440 and the upper contact pad 442 until the force exerted against the diaphragm 424 is so small that the contact between the upper and lower contact pads, 440 and 442, respectively, is broken and the resistance becomes infinite.

The resilient, deformable diaphragm 424 is preferably adhered to the top of the diaphragm spacer 422 by the stop ring 426, which is also adhesively secured around the periphery of the diaphragm 424 so that the diaphragm 424 is held in a tensioned or slack condition between the stop ring 426 and the diaphragm spacer. Referring to Figs. 13 and 14, an alternative embodiment of the present invention is shown comprising a rigid base 412, an alternative flexible base structure 460, a diaphragm spacer 422, a diaphragm 424 and a rigid stop member 426.

As in the first embodiment, the bottom surface of a lower portion 462 of the flexible base portion 460 is adhesively attached to the rigid base 412. In addition, the spacer 422 attaches the adhesive membrane 424 to the flexible base portion 460. A central portion of the diaphragm 424 is then adhesively attached. at an upper or tab portion 464 of the flexible base portion 460.

Referring to Fig. 14, the flexible base portion 460 has a first, generally circular, lower portion 462 which is connected by a hinge or bridge portion 468 to the generally circular tab portion 464 which is smaller in diameter than the lower portion 462. A spacer 466 is adhesively attached around the periphery of the lower portion 462. The spacer 466 is generally a toroidal coil-shaped spacer having a square or rectangular cross-section, the spacer having a central area having an area greater than the area of the tab portion 464. Thus the flap portion 464 is folded to overlie the lower portion 462, it will lie free against it about the periphery except at the hinge portion 468. Thus, the flap portion 464 is free, transversely movable about the hinge portion 468 in the area surrounded by the spacer 466.

In a manner similar to that previously described in connection with Fig. 12, a first conductor 470 extends from a connecting portion 472 and forms a centrally located contact pad 474 in the first portion 462 of the flexible base 460. A second conductor 476 mounted on the base 460 also extends from the connecting portion 472 but extends in a path around the periphery of the first portion 462 around the hinge or bridge portion 468 and forms a contact pad 478 located centrally on the flux portion 464. A suitable semiconductor material layer 480 is provided to cover at least the contact pad 474 and possibly the contact 478. The contact pads 474 and 478 are placed symmetrically on opposite sides of the folding line 486 so that when the flap part 464 is folded along the folding line 486, the contact pad 478 comes in line opposite the contact pad 474.

To obtain a positive movement of the flap portion 464 both toward and away from the lower portion 462 of the flexible base in response to increases and decreases in applied air pressure, the top surface of the flap portion 464 is opposite the surface to which the contact pad 478 is attached adhesively attached to the lower the surface of the diaphragm on a central portion of the diaphragm, laterally spaced from the peripheral edge on the inside of the diaphragm spacer 422. Thus, the tab portion 464 moves as the resilient, deformable diaphragm 424 moves to cause variations in the contact resistance between the contact pads. 474 and the contact pad 478 in response to variations in the pressure applied to the diaphragm 424.

The pressure transducer in accordance with the present invention can be used in a number of devices. But a particularly advantageous use is that of an electronic saxophone-like device 500, as illustrated in Fig. 15, with a nozzle 502, an air chamber 504 and a pressure transducer 506 located at the end of the chamber 504 with the diaphragm facing inwardly towards the chamber 504. A plug 510 is inserted or otherwise sealed in position at the mouth end 508 of the saxophone-like device to rigidly hold the pressure transducer 506 in position. An additional pressure transducer device 112 may also be located at the nozzle to be compressed with the lips. A connecting part 514 is connected to the connecting part 428 or 472 (Figs. 12 and 14, respectively) or to the connecting part 532 in Fig. 13, which will be described later, by the selected pressure transducer according to the present invention. A suitable electronic tone generating circuit 516 is connected to the connecting part 514 so that e.g. the volume of the tone generated by the tone generating circuit 516 can be varied in response to variations in air pressure in the chamber 504. Thus, the stronger the user blows in the nozzle 502, the greater the generated pressure in the chamber 504 and the stronger the generated volume.

Referring to Fig. 16, an alternative pressure transducer in accordance with the invention is shown.

In particular, the pressure transducer includes a first support member 530 which may be flexible or rigid (eg, a PC disk), a second support member 534 and a connecting member 532 extending from the first support member 530. A spacer (not shown) is adhesively attached around the periphery of the first support member in a manner similar to that previously described in connection with Fig. 14.

Of course, although the first support member 530 and the second support member 534 are shown as separate parts, they may also be a single member connected by means of a hinge member as in Figs. 12 and 14, in which case the second support member adhesively attached to the diaphragm pivots around the threaded part as the diaphragm moves in and out. However, since the second support part only provides a shunt support, a conductive connection over the thread is not needed in this embodiment as will be described below. Thus, the second support member 434 can be separated from the first support member 430 and the second support member 534 can be easily adhered to the diaphragm so that the second support member 534 moves with the diaphragm. A particularly convenient method of doing this is to spray or fabric print semiconductor material on the surface of Packlon tape, which is a printable tape produced by 3M Corporation. A circular dot of this semiconducting, covered tape is then placed on the membrane opposite the first support member 530.

To obtain a transducer device according to this shunt embodiment, a first conductor 540 is mounted on the surface of the first support part 530, the first conductor 540 comprising a first contact part 542 with a plurality of interdigitating fingers 544 and a second contact part 546 also having a a plurality of interdigitating fingers 548. The interdigitating fingers 544 and 548 interleave with each other in an electrically insulating manner.

A second conductor 550 is located on the surface of the second support member 534 so that when the second support member 534 is adhesively attached to the diaphragm, the second conductor member 550 will be mounted adjacent, transversely aligned with the first conductor 540.

Before the second support member is attached to the diaphragm, a semiconductor material layer 552 is applied to overlie the second conductor 550 to thereby provide a contact resistance between the first and second conductors 540 and 550, respectively, as these two conductors are compressed into electrical contact with each other by movement of the diaphragm. Of course, it will be appreciated that the semiconductor material layer may be applied to either the first or second conductors 540 and 550, respectively, or alternatively the second conductor 550 may be made entirely of the semiconducting material with a separate conductor such as silver or copper. eliminated. Of course, if the semiconductor layer is applied to the first and the second contact part, it is preferred that there is a laterally insulated distance between the semiconducting material on the two contact parts. It will also be appreciated that the special interdigitating fingers may be of any shape and may e.g. be applied to the surface in a circular arrangement. Thus, this implementation works the other. .....__......_.-. a.a. »..,. _; 10 452 925 2 ° the conductor part as a shunt between the first and the second contact part.

The spacers are preferably of the thickness of a piece of commercially available adhesive tape and that the miller, in the preferred embodiment, has a thickness of about 3 m. The contact pads can be of any suitable size and shape and can e.g. be circular with a diameter of about 6.35-12.7 nm. Finally, in the previously described embodiment where the semiconductor tape dot is attached to the surface of the membrane, only one of the spacers 420 or 422 is required. Although various embodiments of the present invention have been described, it will be appreciated that a variety of other modifications and embodiments may be made. the present invention. Thus, it is an object of the claims to encompass all such modifications which fall within the scope of the invention.

Claims (3)

10 15 20 25 30 35 40 452 925 21 PATENT REQUIREMENTS Bounce-free switching apparatus having a boundary layer resistance which varies inversely with a pressure applied vertically thereto, comprising a first conductive part (132), a pressure sensitive bearing (134) and a second conductive part (138), characterized in that the pressure-sensitive layer (134) comprises a semiconducting material arranged to cover the first conductive part (132) with intimate electrically conductive contact therewith, the pressure-sensitive layer (134) having a first surface (136) with a plurality of microscopic projections of semiconductor material extending from the first surface to provide a plurality of surface contact points, and that the second conductive member (138) is located in a substantially non-electrically conductive relationship with the pressure sensitive bearing (134), whereby the bounce-free switching device is normally open, closing the bounce-free switching apparatus depending on a compressive force applied to force the second conductive part (138) and the first surface (136) to increase the physical contact between the microscopic projections and the second conductor (138) and thereby enable an electrical conduction through the affected microscopic projections, the electrical conductivity increasing as the value of the compressive force increases and decreasing as the value of the compressive force reduction. (Fig. 5) A bounce-free switch apparatus (100) having a surface contact resistance which varies inversely with a pressure applied vertically thereto comprising a first conductive member (104), a first pressure sensitive bearing (106) and a second conductive member (112), characterized in that the first pressure-sensitive layer (106) comprises a semiconducting material, which is arranged to cover the conductive part (104) with intimate electrically conductive contact therewith and which further has a first surface (108) with a plurality of microscopic protrusions extending therefrom, and in that the apparatus further comprises a second pressure sensitive layer (114), which comprises a semiconducting material arranged to cover the second conductor (112) with an intimate electrically conductive contact therewith and further having a second surface ( 116) with a plurality of microscopic projections extending therefrom, the first (108) and the second (116) surfaces being located in a normally electrically non-conductive relationship with each other, and at least one of the first (104) and the second conductive part (112) is resiliently movable depending on a compressive force applied thereto, so that the microscopic projections extending from the first (106) and the second (114) pressure sensitive the bearing, are brought against each other, to enable electrical conduction between the first (104) and the second (112) conductive part, the electrical conductivity increasing as the compressive force increases and decreasing as the value of the compressive force decreases. (fig 2) 10 15 20 25 30 35 40 452 925 n Apparatus according to claim 1 or 2, characterized in that the semiconducting material is particulate molybdenum disulfide.