DE2539561A1 - Capacitive touch plate semiconductor switch for keyboards - has touch capacitor operating amplifier between load and signal source - Google Patents

Abstract

The capacitive touch plate semiconductor switch, for keyboards, is simple and cheap and has a touch plate (11) with metal coatings (10, 12) on each side of its insulating main body. One coating is touched by the users finger and the other is connected to the base input of a transistor amplifier (24). The transistor is connected by its emitter to a signal generator (16), by its collector to the output load (20), and by its base to the touch plate capacitor. The transistor has its base emitter junction shunted by a capacitor (26) and by a resistor (28). The transistor may be replaced by a differential amplifier.

Description

Circuit device to be actuated by a change in capacitance Die The invention relates to a circuit device to be actuated by a change in capacitance.

There are already non-mechanical or solid-state switches that work through one touch operated, toggle switch and microswitch.

The switching process happens in most cases in that the Current flow is limited or interrupted by a mechanical contact. However Some touch switches do not use mechanical contacts. It it is known to ionize a gas in order to make it conductive in order to generate a signal or to enable the conduction of a signal by a device a voltage is applied to neon tubes, which makes the gas non-conductive, until it's ionized. Only at this point in time is a signal transmitted, as a result of which a switching function is generated.

Other solid state switches have a photoelectric device present in order to influence a light detection device in such a way that a switching function occurs. Other solid-state switches, in turn, use the interruption or line of light through optical devices, which then generate a signal which is sent to the Effecting a switching function is used.

The solid-state switches mentioned above have complicated movements and operations necessary before a signal for a switching operation is generated. By these movements often make such signals imprecise and generate the switching function not in the desired way.

werner, such solid-state switches are complex and expensive, making them very expensive. Often times, the cost increases because several Electron tubes and other active and passive components are needed that have nothing at all to do with the actual switching function, just used to register a signal.

It is easy to see that solid-state switches are extremely suitable to avoid contact bounce and undesired voltage peaks.

In known switches and converters, electrical signals are often used generated, which are analogous to certain mechanical movements, so that a signal which is an ON or OFF state, a proportioned movement , an analog movement or a linear movement. Draw such converters are not characterized by a particular linearity and can be used in many applications not be used in a cheap embodiment. As a result, the Uses of transducers are limited and when they are needed they often arise constructive difficulties with additional costs.

An object of the invention is to provide a switch and converter which is cheaper but better than known solid-state switches, and is characterized by good linearity.

In the case of the switch or converter according to the invention, a signal with steep flanges are used, which preferably have the rise of a step function where the signals are provided by a signal source such as a clock will. A transistor is switched on or off by the signal source and depending on the capacity of the capacity sensing device. It's a circuit provided by the switching or the transfer of a certain mechanical Movement can be easily registered and a corresponding analog signal generated can. The switch of the present invention is extremely reliable and overcomes many the previously known switching difficulties. Furthermore, the switch can be cheaper and can be manufactured with a wider range of uses, thereby making the well-known switches such as microswitches, switches for analog functions, GeIRuse for electronic devices and general switching functions for computers are replaced.

The converter according to the invention is characterized by great linearity the end. Furthermore, this transducer can be designed so that it can be used to measure liquid levels, the movement of precision equipment and many other uses in which certain mechanical movements are to be converted into an electrical quantity, can be used.

In known switches, the signal can be changed by means of the amplitude will. However, in most cases a threshold detector is required. By The object of the invention is to obtain a signal with its full amplitude.

The object of the invention is a wide phase modulator This phase modulator or frequency modulator has the advantage that it is a Single pulse technique used.

This saves a lot of energy, so that the The limits resulting from the total energy of the system are less restrictive. Further can be the subject of the invention in general in the field of digital technology be used.

In general, the invention relates to a device for generating of a signal due to a change in capacitance.

In particular, by the device according to the invention in its simplest embodiment generates a signal when a change in capacitance is caused by it is perceived that a transistor or amplifier is in a circuit with a signal source whose generated signals have rising edges according to a step function) n are controlled. The switching device comprises together with a transistor or amplifier a capacitance detection device, whereby a signal with step-shaped Rising edges or a rapidly rising signal is supplied. With others Embodiments, the signal source can be designed in various ways and used as an energy source for the switch. The switching operations too at the keys of a calculator or other device with a clock or a signal with a stepwise rising edge can be used as the signal source can be used in embodiments of the invention. Furthermore, optionally Equalization and temperature compensation devices such as differential amplifiers be used.

Another embodiment of the invention provides a transducer that Demonstrates changes in capacity in relation to its mechanical parts. The capacity changes influence a supplied signal, which has a step-shaped edge, so that changes in capacitance detected in either a proportional, analog, linear, or on-off manner can be. This generates a suitable signal to detect changes in movement or indicate an on-off change.

Embodiments of the invention are described below with reference to the drawings described.

1 shows a schematic representation of the simplest embodiment of the invention Fig.2 shows a schematic representation of the invention with certain Compensation elements.

3 shows a schematic representation in block form of one with the Invention to be used differential amplifier.

4 shows a schematic representation of the invention, the Signal source is used for power supply.

5 shows a section through a schematic representation of a Converter that can be used with the invention.

Fig.6 shows the representation of a circuit, which together with the transducer according to the invention can be used.

Fig.7 shows a transducer for level measurement, which together with the in the circuit shown in Fig.6 can be used.

8 shows the schematic representation of another according to the invention Converter.

Fig. 9 shows another embodiment of a converter.

Fig.10 shows a bimetal or membrane cooler, through the pressure or Temperature changes can be detected and used in the invention can be.

Fig.11 shows the schematic representation of several transducers that the Movement of an object moving along them prove can.

Fig. 12 shows the schematic representation of a control panel with a button or touch switches.

13 shows the schematic representation of an embodiment of the Invention through which certain ranges of movement of an anchor can be proven, without the armature having to be electrically connected.

Fig. 14 shows a diode decoding matrix for use with the invention, whereby the keyboard for a calculator can be made.

Fig.15 shows a schematic view of another embodiment.

form of a transducer for determining the level of a liquid or a other substance.

In Fig.l is a basic embodiment of the invention with a tactile or Cover plate 10 shown. This can be made of any suitable material such as e.g. plastic and serves as a visible circuit board. It is sometimes pale, push-button switches to be recessed, e.g. in elevators. The plate 10 can thus be arranged sunk or against accidental contact be protected by the fact that edges protrude or that they are from a movable one Cover is covered.

A metal plate 12 is arranged opposite the touch plate 10.

The touch plate 10 acts as a dielectric to the conductive plate 12 opposite any external source lying outside the tactile plate 10 isolate. In order to achieve an effective capacity increase when the plate 10 is touched to generate electrons between the plate 12 and the body of the person, that the tactile plate 10 touches can be stored. The capacity at this invention is represented by the body of the person concerned and the plate 12, which are separated from one another by a dielectric 10. As a dielectric you can either use a plastic or any suitable insulating material or use an air gap with a very thin plastic.

An electronic clock or signal source 16 is on one Page 18 is connected to ground and has an output 20. The signal source 16 should emit a signal, the edges of which form step functions, as is the case with the signal train 22 is shown. The signal 22 may have a substantially rectangular shape However, the signal can also have a shape which essentially corresponds to a rectangle. The essential property of the Signa: .s is that at least one flank is essentially a step function. In other words, that from the signal source! emitted signal should have sufficient amplitude and frequency to be able to cope with the elements of the invention to work together.

The signal source 16 is at its output with the emitter of a transistor 24 connected. The base of the transistor 24 is connected to the conductive plate 12. Between the base and the emitter of the transistor 24 are a capacitor 26 and a resistor 28 connected in parallel with one another. The capacitor 26 serves to the right balance in terms of the capacitance of the transistor and the others To create capacities of the circuit. The resistor 28 serves as a bias resistor, to prevent transistor 24 from operating in an undesirable manner. With In other words, when the transistor 24 has a leakage current from the collector to the base occurs, the resistor 28 acts on the transistor 24 that the leakage current the Invention not operated, as will be described. Resistance 28 also serves for unloading.

The collector of transistor 24 is connected to a junction. At the connection point 27, a resistor 29 is connected, which any can be low-impact and suitable stress, as it will be described below. the The circuit described can be used both with a PNP and with an NPN transistor work. However, the working characteristics then differ from one another.

The switch works with the plate 12 along with a touching one Body, whereby the signal generated by the signal source is connected to ground or completes the circuit to transistor 24 or amplifier. this happens due to the capacitive action between the body and the plate t2, which together form a capacitor.

The signal source 16 generates a signal whose amplitude is zero up to a second potential. This signal is on line 20 at the output released with this specific potential. As mentioned earlier, the signal source should 16 emit a signal, the edge of which essentially represents a step function, such as a rectangular shape.

In the case of a positive signal emitted by the signal source 16, receives one this at junction 30 and at the emitter of transistor 24. If a capacity increase results from the fact that the plate 10 is touched, or if a body is in the vicinity of the plate 12, this capacity increase serves to the fact that electrons flow in the direction of the signal source 16. Likewise through it Electrons moved to the base of transistor 24, causing an emitter current to flow. When the NPN transistor in this circuit works, it becomes more efficient Way converted into the non-conductive state by a retroactive bias.

It should be noted that transistor 24 is an NPN transistor is. With a PNP transistor one achieves the same effect if the signal source 16 goes negative. In the embodiment shown in Fig.1 with the NPN transistor electrons flow from the emitter to the base of the transistor when the signal source 16 goes negative. This is because the capacitor is charged more positively than the signal source 16. As a result of the previous increase in capacitance, the transistor 24 switched to the on-state, so that electrons to the load 29 or the collector and the load can flow.

Incidentally, it should be noted that the resistor 29 is any load in the line can be.

The resistor is for the collector of transistor 24 a Load and a bias generated. Resistor 29 should have a positive Terminal be connected so that the correct voltage for the transistor 24 is supplied will. If a PNP transistor is used, resistor 29 should match the negative Connect a voltage source to the correct one for the PNP transistor Supply voltage.

The resistor 28 forms a discharge path for the capacitor element 11 to signal source 16 and also a drain for leakage current from the collector to the base of the transistor 24. As already mentioned, the capacitor 26 is only the same the capacitance of the transistor 24 and the capacitor element 11, which the cover 10 and the plate 12 includes, and also other stray capacitances.

It should be noted that the frequency source or the general Resize from ZERO to a positive waveform or any other suitable Limitation on size and polarity by any suitable signal generating device can be formed. However, the waveform should be in essential have the edge of a step function, as the impedance of the capacitive Machweiselementes 11 is inversely proportional to the magnitude of the signal change. In other words, if the amount of change or rise in the waveform to the extent that it is a The rectangular pulse increases, the impedance of the capacitive element 11 decreases. As a result, the sensitivity of the specified circuit can be reduced by low Changes in the signals of the signal source cannot be guaranteed.

The signal source 16 can be used to generate a signal with a suitable voltage to operate the entire circuit. This is generally shown in Fig.4 and will be in more detail with reference to this figure described. Although the basic circuit of the switching arrangement shown in Fig.l does not use the voltage output by the signal source 16, as it does with others Embodiments of the invention is the case, however, it should be borne in mind that such a function of the signal source is used in the broadest sense in the invention can be.

In the embodiment according to FIGS. 2 and 3, there is a touch plate like the plate 10 shown. For the sake of simplicity, d: Le tactile plate is obtained 10 and the conductive plate 12 in the other figures. The same reference numerals, there they are used in the same way as in the embodiment according to FIG. An air gap is formed by a space 14. Any other suitable dielectric can be used when the touch panel 10 does not have a sufficient dielectric size Has. The switching elements of the other figures are designed in an analogous manner and result in the capacitive detection function of the entire element 11 in the same way. It should be noted that the tactile plate 10 is the correct one Must have thickness so that Edh dS necessary capacitance between the conductive plate 12 and a neighboring one Body forms. With the same circuits with the same values, the tactile plate 10 can have a suitable thickness and the may touch conductive plate 12, or have the same dielectric requirements be met in that a thin plate 10 and an air gap are provided.

In the embodiment according to FIG. 2, the transistor 24 is used as an amplifier used. Figures 2 and 3 are the same in that it relates to the amplifier, however, the amplifier is shown in detail in FIG. The one labeled 40 Amplifier in Fig.3 is the area bounded by a broken line 2, which is denoted by 40, analogously.

The amplifier 40 operates as a push-pull amplifier with a higher Li> isturz The amplifier 40 can better compensate the temperature influences and other changes, than is the case with transistor 24 only.

2 and 3 it can be seen that between the tactile plate 10 and the conductive plate 12 an air gap 14 is provided. It has already been mentioned that a dielectric such as a thicker non-conductive plate 10 in place of the air gap 14 can be used. The device according to Figure 2, which is a further developed Version of that of Figure 1 comprises two NPN transistors 42 and 44, in one Push-pull circuit. The resistor 46 fulfills the same function as the resistor 28.

Resistor 48 serves to bias the emitters of the transistors 42 and 44 so that they work in push-pull.

A second transistor 50, which is a PNP transistor, is used so that a greater performance is achieved. Resistors 52 and 54 are used to generate a bias voltage. The capacitance in the device is balanced by a capacitor 56. Man sees that the device according to Figure 3 is essentially the same as that of Figure 2 and comprises bias resistors 62 and 64 and a third resistor 6o, which is used in the same way as the resistor previously described will and the the function of the resistor 28 in the device according to Fig.l is analogous. The capacitor 66 increases the capacitance.

of the amplifier 40 and also other capacitances present in the circuit balanced. In the devices according to Fig.S and 3, the signal is through a suitable signal source generated, which is connected via lines 68 and 70, which correspond to the output line of the switch and the input line of the signal source . The lines 72 and 74 of the circuits according to FIG. 3 and according to FIG. 2 are on Ground, with the positive potential connected to the upper part of the circuit As can be seen from the figures.

The signal emitted by the signal source may not be square Shape 76 or a relatively rectangular shape 78.

In order to achieve an optimal working method, the flank should have a Step function correspond.

In the embodiment of the invention according to Figure 4 are a Tasplatte 10, which corresponds to that of the previous embodiments, and a conductive one Plate 12 provided so that a capacitive element 11 is formed when a Body located in the seams of the conductive plate 12. In this embodiment the circuit is supplied by the signal source. The signal is over the line 80 is supplied and removed on the line 82.

The amplitude of the signals should be around 3 volts or more, so that the appropriate power can be supplied to the circuit. The conductive plate 12 is connected to a differential amplifier 92.

With the exception of the capacitor 94, the device is correct according to FIG 4 essentially corresponds to those of FIGS. 2 and 3. Through the capacitor 94 transient voltage spikes from the signal source are absorbed. It should be noted that the output of the signal source 82 is switched in this way is that transient voltage spikes occur because over those the voltage is fed. The temporary voltage peaks are:? - essentially through the capacitance 94 suppressed.

A second capacitor 96 serves in the same way as the other Capacitor in the previous circuits added to the capacitance in the circuit balance. Via resistor 98, the amplifier is biased so that it is normally in the off state. The resistors 100 and 102 serve as series resistors to the differential amplifier the clock signal in the right way to feed the semiconductor elements contained in it work in the cheapest way.

In other words, resistors 100 and 102 also serve as a gate voltage resistors to ensure good functioning of the semiconductor elements of the differential amplifier 92 to effect. The resistances in the embodiment according to FIG. 4 are essentially the same as those in Fig.2. In particular, the resistors correspond to 52 and 54 resistors 100 and 102.

In the Fig.4 an embodiment is shown, which with a differential amplifier works, which results in the associated special advantages. Further at the same time the signal source is used to power the circuit to supply, In summary, it results for the basic principle of the above Devices that the immediate voltages or potentials on the capacitor plate 12 and the signal voltage are compared with each other. You can see that the Circuits of the above embodiments have a commonality in terms of resistors is present. Essentially, the corresponding resistors 28, 46 and 60 are with connected to an amplifier, about the immediate tension between the signal and the capacitor plate 12 to compare and gain a gain to cause an appropriate signal to be generated by devices 24, 40 and 92 will.

It is emphasized as essential to the invention that the method of operation the circuit does not depend on changes in amplitude. Of particular importance is that the operation of changing the frequency or the edge of a step function depends.

The circuit according to the invention is the edge of the step function changed and this results in the effect of a flank difference. the The operation of the circuit according to the invention is achieved by differentiating the Flank causes.

According to the invention is a step function or a potential increase provided that within a predetermined time interval from a voltage on another takes place. The amplitude remains essentially constant. The signal will fed to a secondary branch and compared with the input, the output is formed by the difference. In other words, the slope rises as it increases Capacity slower. This is especially important in the present case the amplitude does not change, but its rise time or frequency.

According to Figure 5 is a converter with the circuit described above associated with this invention. The converter can be used together with the circuits of Fig. 1, 2, 3, 4 and 6 can be used.

The transducer according to Figure 5 can work as a motion switch, wherein the capacitive properties of the device are exploited. In particular, can the armature 107 are moved to a corresponding to the mechanical movement of the armature 107, generate electrical signal. Furthermore, the armature 107 can be loaded by a spring so that it can return to its original position.

The transducer according to FIG. 5 has an armature 107. An inner housing 110 is surrounded by an outer, metal housing 108. The housings are cylindrical designed and aligned in the axial direction to one another.

The inner housing 110 is preferably made of an insulating one Dielectric such as a ceramic material, plastic or Teflon, whereby good mechanical operation results; The internally arranged anchor 107 is made of metal and can be conveniently located between the walls of the interior Cylinder 110 moved.

A conductive connection 112 is attached to the outer metal tube 108, the one with the connection point at which the conductive plate 12 of the capacitor element is normally 11 is connected, connected in the circuits according to FIGS. 1, 2, 3, 4 and 6 is.

The armature 107 can be with a slip ring or sliding contact, which generally as shown as connection 114.

Connection 114 should be at ground or a lower potential be connected as connection 112, creating a situation in which a displacement of the armature 107 is necessary for the operation of the circuit Changes in capacitance caused. In some cases, a ring around the Armature 107 creates a sufficient "ground" below the potential of the armature in order to effect the desired change in capacitance, in Figs a converter cooperating with a circuit according to the invention is shown. The connection of the converter of FIG. 7 with the circuit of FIG. 6 is carried out in a similar manner Way, as with the connections already described between the converter and the various circuits of Figures 1 to 4.

The circuit of Figure 6 comprises a differential amplifier with NPN transistors 42 and 44. In the circuit of Figure 6 is a capacitor 122 provided, through which this circuit is essentially only from that according to Fig. 2 differs. In some cases, the same reference numbers are used for the designation. The capacitor 12 in the circuit according to FIG to create closed amplifiers or functional amplifiers. The capacity of one Converter is used to supply the amplifier with an input signal. The condenser 122 is a coupling capacitor to allow feedback from the output to the negative Generate input of the differential amplifier.

In FIG. 6 a summing amplifier is referenced at the negative input ip provided on the positive. The change in capacitance of a transducer such as the one 7 causes a change at the summing point 126. The summing becomes a change in either the positive or negative current depending on it how the signal source is connected to lines 71 and 73. In other words, when the signal source becomes positive or negative, a positive resp. negative change3 at summing point 126. The change is proportional to the capacitance, since it relates to the total capacity, and not necessarily to the change of incremental, discrete capacity changes. Any capacity increase that forming a discrete output of the entire, proportioned change makes itself noticeable in their entirety at the summing point 126.

Another embodiment of a transducer according to the invention is shown in FIG Fig.7 and works together with the circuit according to Fig.6. Through the Transducers can measure the changes in the level 130 of a liquid column 128 will. The liquid level 130 is within a non-conductive container or plastic container 132 is shown. The container 132 serves as an insulator for the electrodes of the circuit. The conductors 134, 135 and 137 can be arranged on the outside of the container in a suitable manner. The ladder 134 and 137 are connected to a lower potential with respect to conductor 135 or lie on ground. Conductor 135 is analogous to the input of the circuitry Connected like the conductive plate 12 of Figures 1-4. In the present example the conductor 135 is connected to the connection point 200 of the circuit according to FIG.

It should be noted that when the container 132 does not consist of a insulating material is made, the conductor 135 or the input of the transducer must be isolated from the container, so that changes in level of the liquid 128 capacity changes result. This embodiment is shown in Fig.15 together with shown as a conductive container. In the container 332 is a liquid level 330 available. Further, a tube 334 is made of a non-conductive material such as e.g. glass or plastic arranged. A conductor 335 is provided in the tube 334 that on the circuits in the same way as the conductor 135 at the connection point 200 can be connected.

With this embodiment, the stand 330 of a substance in the Container 332 are set aside, with the substance being a bulk material or a liquid can act.

In Figure 8 is another embodiment of an inventive Converter shown to which an output line 150 is connected. This line is in the same way as the plate 12 in the above circuits according to Figure 1, 2, 3, 4 and 6 connected. The transducer according to FIG. 8 has two separate plates 152 and 154. The plates can be made of a metallic material such as it is the case with most capacitors A dielectric Element 156 can be moved between capacitor plates 152 and 154. By the movement of the dielectric element 156 results in a change in capacitance Line 157 connected to plate 154 is grounded or lower Potential.

In the embodiment according to FIG. 8, a signal is generated which the change in capacitance between plates 152 and 154 is equivalent. The advantage In this embodiment, a dielectric such as the element 156 can be moved between two electrical conductors, and that eth essentially the mechanical movement equivalent linear signal is generated.

The embodiment shown in Fig. 12 is similar to that of Fig. 8, because here too a dielectric such as a plastic anchor 158 between two plates or metal tubes 160 and 162 is arranged. The anchor 158 is on one side designed as a push button 164. Thus, an armature 166 can be made from a suitable dielectric used to move between tubular members 160 and 162, thereby changing their capacity.

The tubular member 160 is as shown in the above circuits FIGS. 1, 2, 3, 4 and 6 are connected to that point via a line 168 to which the conductive plate 12 is connected. The tubular member 162 has a lower potential or is connected to ground via line 170.

The converter shown in Fig. 12 can have a switching function are generated 'together with a keyboard on a computer related can be, so that with this converter you feel as if you are operating it by hand Switches received. Sometimes it is necessary to perform a manual operation to be provided so that one perceives that a switch has actually been operated.

In the embodiment according to FIG. 9, there is a movable part 174, which is at ground or a lower potential.

Together with the plate 172 it is used to ensure that capacitance changes can be generated. It is well known that by changing the distance a change in capacitance can be achieved between two plates, whereby the capacitance is inversely proportional to the plate spacing. As a result, the capacity is changed, when the movable member 174 moves with respect to the plate 172. Of the Output 176 can be connected to any of the circuitry previously described at the point to which the conductive plate 12 is connected, thereby generating a signal which is equivaltent of the linear movement of the movable member tes 174 is. The connection to plate 172 can be made in any suitable manner will.

The other part of the transducer must be connected to ground or to a lower potential are placed over the lines 178 and 180, which are connected to the Halteblöc; cen 182 and 184 are connected. Thus an effective earth connection with the moving one Part 174 is made, it should be in contact with retaining blocks 182 and 184 stand or be electrically connected to them. Furthermore, the movable element should 174 isolated by an insulating washer or an insulating material 183 and 185 will. As the gap 186 increases, there is an effective change the capacitance between element 174 and plate 172, thereby adding to the ~ line 176 a signal is generated. It is not necessary that the plate 172 or the Element 174 itself move right, just that relative Movement occurs between them. Furthermore, the movable member 174 and the Retaining blocks 182 and 184 may be tubular or rectangular.

For example, the device according to FIG. 9 could be a micrometer a machine tool, changes in length translate into changes in capacity implemented. With the invention, a limited measurement of the length of movement, as required by a micrometer. Regarding the capacity changes between the plate 172 and the movable member 174 are extremely accurate readings which results in a substantial improvement in the accuracy compared results with known instruments.

In the embodiment shown in Figure 10, there are a pair of supports 188 and 190 shown in their interaction with other parts. The pillars are connected to ground via lines 192 and 194. The supports lying on the ground 188 and 190 are in electrical communication with a deformable part 198 and cooperate with them. The operation of this embodiment is the same Principle like that of the embodiment according to FIG. 9 with regard to the capacitance changes based on a distance change 196. The one occurring in this embodiment The change in distance is analogous to the change in space 186 in FIG. 9 and is used for exploited the way the connection works.

When working, the deformable, grounded part 198 used so that it is deformed in the direction of arrow 200 to a change of the space 196 to generate the distance between the plate 198 and a fixed Capacitor plate 202 affected. When the plate 198 is deformed, it changes through this the distance, causing a change in capacitance between them and the plate 202 is caused. The plate 198 can also be used as a bimetal element, similar to those used to detect temperature changes be. Thus, the device according to FIG. 10 can be used to display temperature changes can be used if the plate 198 is designed as a bimetal element.

An analog output can be provided on the plate 202 via a line 206 can be obtained. The line 206 is connected to one of the connection points, to which the conductive plate 12 is connected in the circuits already described is.

In addition to the temperature changes already mentioned, which are caused by of the device according to FIG. 10 together with a bimetal element 198 pressure changes at the top can also be achieved by this device of the plate 198 can be established. For example, when a positive ambient pressure occurs in the direction of arrow 200, the plate or membrane 198 is deformed, when the internal pressure in the space 196 is sealed off from the external pressure Pressure change is shown as an analog, electrical output to the amplifier, which is over line 206 is connected.

In Fig.11 an embodiment is shown in which the invention is used as an encoding function in that a movable plate 210 which is connected to ground via a line 212, several plates or sensing elements 214, 216 and 218 is superimposed. The plates 214, 216 and 218 each have lines 220, 222 and 224, respectively, to the corresponding connection point of the preceding amplifier circuits be guided. In this way an electronic encryption or encoding can be used when the movable plate 210 moves with respect to FIG the Plates 214, 216 and 218 shifts.

Side grounding plates 215, 217, 219 and 221 are grounded or connected to a lower potential. When the plate 210 is above the corresponding Capacitor plates 214, 216, 218 moved, they are either in an or off state, so that encryption or encoding is performed as a result can be.

In Fig. 13 are a plurality of axially aligned, conductive cylinders 230, 232 and 234 are shown. The cylinder 234 has a pair of ground connections 236 and 238. Cylinder 230 is also connected to ground via lines 240 and 242. The aligned cylinders are axial with respect to a metal armature 244 aligned, which is attached to an insulator that is in the shape of a second anchor 248 so that armature 244 is substantially electrically isolated. In cylinders 230, 2i2 and 234 is an insulating or dielectric cylinder 250 arranged concentrically with those, so that the metal armature 241 opposite those cylinders is isolated. The cylinder 232 is connected to one of the cylinders via a line already described circuits connected to the corresponding connection point, whereby the capacitive coupling takes place in this circuit. When the device works, discrete changes in capacitance can be analogous to linear, mechanical changes Movement of armature 244 can be sensed by cylinders 230, 232, and 234.

A keypad 500 with keys 0, ..., 9 is shown in FIG.

The keys can be used, for example, by the key 164 according to FIG.

12 are formed, or a tactile plate 10 can be. It is one Group of circuits 1, 2, 4 and 8 provided through which the actuation of the Keys is registered in binary form. When the buttons are pressed, the Interaction with the diode decoding matrix and the circuits that support such which may be shown in Figs. 1, 2, 3, 4 and 6 causes a single or a combined electrical signal which is equivalent to the numeric key will.

The circuits of the binary system can receive signals from a signal source 16 received, which operates these in parallel. Of course, the signal can be parallel to the Order of a time base or in some other way. Regardless of this, it should be noted that the switching function is only a signal source required, which is independent of the amplifier shown in Figures 1, 2, 3, 4 and 6 can be provided. In other words, if a computer already has its own time base has, so this can be done with the switches according to the invention instead of the above Circuits specified in the signal source.

Referring again to FIG. 1, it can be seen that a switch with a metallic or conductive surface 12 together with a dielectric 10 is used. The touch-sensitive § metallic material can be shielded or on the back of a transparent plastic or glass material, that forms the plate, be deposited, e.g.

by means of a vacuum coating process or any other Process for applying a metal layer. Some glasses already have a layer of tin oxide or some other material to create a reflective effect or so that they are only transparent in one direction.

The mentioned plate can be through a touch sensitive cathode ray tube are formed, the dielectric material 10 and the metal coating 12 are transparent.

It has been found that by using a plastic or Glass, which lies over the cathode ray tube, a switching function with certain, metal contact points 12 can be achieved. In particular, lines or different grid locations are produced by the dielectric material 10 thereby will, that the metallic material 12 is applied with such a geometry.

For example, lines that stretch across the plastic can be used or extend the glass that is being metallized.

The lines can be one switching area on the panel that is on the cathode ray tube rests, indicate so that when a specific information is on the screen can be seen, a reaction to this can take place in that the visually with it connected switching area is touched. For example, if you have multiple questions in a medical examination can be made visible on a screen, the interviewee Person respond by touching the area of the dielectric cover 10 is, under which the metal switching portion is arranged.

It is known that questionnaires with different responses are patlents were submitted and one of five questions had to be answered. It can for example an affirmative or negative answer or else, that a special condition should be specified. As a result, the questions can are presented in this way and the answer is recorded by which area, which is particularly related to the question has been touched. The answer can then be recorded using a computer that comes with the questionnaire in the picture-.

umbrella cooperates. On the screen of the cathode ray tube can be applied a metallic layer over which a dielectric material in the essentially similar to the dielectric material 10 is placed. In other words, a thin metal film 12 can be applied to the cathode ray tube.

The dielectric 10 used can be in the form of a foil, d-ie e.g. made of a thermoplastic material. Besides that already a touch-sensitive screen can be used with the the metal Part 12 from several areas in the form a matrix or a grid that extends over the entire screen extends. In the case of a screen measuring 25 x 25 cm2, for example, several metal Matrices 12, which are located under the dielectric material 10, are used, all of which are connected to a decoder. In other words, it is not necessary to have one for each specific metal area 12 on the Screen of dielectric material 10 has a switch. The unit can be related are, with a decoding matrix similar to that shown in Figure 14 with a limited number of switches working together. So it is possible to use the XY coordinates the location of the corresponding metal conductor 12 in any particular area to decode with the help of a decoding matrix.

It has been found that through the cathode ray tube sometimes a space charge or interaction with the capacitive coupling on the metal Material 12 occurs. This can be prevented that between the metal Material 12 and the screen either a grid or a transparent metal layer is arranged to discharge the space charge.

It can be seen that the above switch plate cover for a Cathode ray tube coupled with some particular computer or information can be customized on the screen. Commands that relate to those on the screen The information shown can be used, as can the transmission of signals related to the information presented as long as the switches on plate 12 correspond to the signals dielectrically coupled therewith and generate them.

To a multi-area grille design according to the invention with a simplified To form circuitry can be related to a cathode ray tube with a conductive plate will. In such an embodiment, a conductive surface 12 is provided with a non-conductive Cover plate such as a dielectric 10 provided " The conductive layer 12 is placed on the cathode ray tube so that it fits the electromagnetic Radiation experiences at the point where the specific image on the screen he follows.

Especially if a letter of any other shape or a Character emitted by the cathode ray tube creates an electromagnetic Radiation that corresponds to the specific image on the tube.

The conductive plate receives the radiation related to the Time and position coincide with the picture on the tube Finger on the conductive surface, which is separated by a dielectric 10, there is a decrease in the output signal from the conductive plate 12 associated with the image of the cathode ray tube through which the information is delivered is coincided. This causes a switching function that corresponds to the point of Scanning of the cathode ray tube coincides, which of course with the control voltages the cathode ray tube can be compared to get the appropriate location.

The electron beam of the cathode ray tube causes a visible one and electromagnetic projection from the surface of the tube. As a result of that if a conductive surface 12 is arranged on the screen, that of the coincides Conductive surface 12 signal originating with the electron beam of the tube.

It should be noted that many other embodiments of the Invention can be used, inter alia, the circuits shown for generating a switching function or for converting an information field or data field.

Claims (25)

PATENT CLAIMS . -a electrical circuit device, g e k e n n n z e 1 c h n e t, by a capacitive sensor (11) with a conductive surface (12), whereby a capacitor element is formed with a body located in the vicinity, and by a signal source (16) connected to the conductive surface which can generate a signal with at least one essentially socket-shaped flank is, whereby the circuit device can be controlled, and by one with a elektrisebhm load (29; 55) connected amplifier (24; 40; 92) to the conductive Surface (12) and the signal source (16) is connected. 2. Circuit device according to claim 1, characterized in that g e k e n n -z e i c h n e t that the amplifier is a transistor (24), the emitter of which with the Signal source (16) and its collector is connected to the load (29). 3. Circuit device according to claim 2, characterized in that g e k e n n -z e i c h n e t that the base and the emitter of the transistor (24) via a capacitor (26) are connected. 4, circuit device according to claim 2, characterized in that g e k e n n -z e i c h n e t that the base and the emitter of the transistor (24) have a resistor (28) are connected. 5. Circuit device according to claim 1, characterized in that g e k e n n z e i c h e t that the amplifier is a differential amplifier (40). 6 .. Circuit device according to claim 1, characterized in that g e k e n n -z e i c h n e t that the amplifier is supplied with energy by the signal source (16) will. 7. Circuit device according to claim 1, characterized in that g e k e n n z e i c h n e t that at least one further capacitive sensor is present, wherein there is only one electrical circuit for generating a signal, too which the capacitive sensors are connected in parallel. 8. Circuit device according to claim 7, characterized in that g e k e n n -z e i c h n e t4. that the capacitive sensors (11) as keys in a keypad (500) are arranged, and that a diode decoding matrix between the capacitive sensors (11) and the remaining part of the switching device is arranged. 9. Electrical circuit device in the form of a converter, g e k e n n n e i n e t by a capacitive sensor with a first conductive one Element that can be capacitively coupled to a second element, the first Conductive element arranged to increase the capacitance in relation to an external body and through a differential amplifier connected to the first element (12) (40, 92) and by a signal source (16) connected to the differential amplifier, through which a signal with at least one essentially step-shaped edge in relation to the time and dZ voltage can be generated, and by series resistors (46, 54, 52) for the differential amplifier (40, 92). 10. Circuit device according to claim 9, characterized in that g e k e n n z e i c h n e t that the differential amplifier (40, 92) has a capacitor (56, 66, 96), by means of which stray capacitances can be compensated, 11. Circuit device according to claim 9, characterized in that the differential amplifier (40, 92) can be supplied with sufficient energy by the signal source (16) is. 12, circuit device according to claim 11, characterized g e k e n n -z e i c h n e t that the signal source (16) is connected to a capacitor (94), by the temporary generated by the energy supplying signal source (16) Voltage peaks can be reduced. 13. Circuit device according to claim 9, characterized in that g e k e n n z e i c h n e t that through a capacitor (122) in the amplifier (Fig.6) a negative Feedback can be generated, 14. Electrical circuit device with a capacitive one CONVERTER SIGNED, by means of a capacitive converter with a first conductive element and a relative to this movable, capacitively coupled Part, and by a signal source (16) for generating a signal with at least a stepped edge, and through one with the capacitive converter and the Signal source connected amplifier (40,92) for amplifying a signal 15. Circuit device according to claim 14, characterized in that a dielectric Occupancy is arranged within the first conductive element, the part (107, 244) can be moved within the dielectric coating, causing a change in capacitance can be generated, and that the amplifier is connected to the first conductive element where the part has a lower potential than the first element. 16. Circuit device according to claim 14, characterized in that g e k e n n -z e i c h n e t- that the first element and the part are concentric cylinders. 17.Schaltungeinrichtung according to claim 14, thereby g e k e n n z e i c h e t that an insulating container (132) receives the part, the first conductive element is arranged on the outside of the container (132), and that a second conductive element is arranged on the outside of the container (152), whereby capacitance changes between the first and second conductive elements can be determined when the part changes its position in the container (132). 18. Circuit device according to claim 14, characterized in that g e k e n n -z e i h e t that a non-insulating container (332) receives the part, wherein the first conductive element is disposed inside the container (332) and opposite the container and the substances in it is insulated. 19. Circuit device according to claim 14, characterized in that g e k e n n -z e i c h n e t that a second conductive element is arranged, and that the part (156,166) a dielectric movable between the first and second conductive elements and that one of the conductive elements is connected to the amplifier (40, 92) wherein the second element is a lower or ground potential with respect to the amplifier Has. 20. Circuit device according to claim 14, characterized in that g e k e n n -z e i c h e t that the first conductive element (172) is connected to the amplifier (40) is, and that a movable, conductive block (174) is arranged through which the Gap (186) between the block and the first conductive element (172) Change in capacitance is changeable, and that subsequent to the conductive block (174) a second conductive element (182, 184) is arranged to a in relation on the first conductive element (172) to generate a lower potential. 21. Circuit device according to claim 14, characterized in that g e k e n n -z e i c h n e t that the part (198) at a distance from the first conductive element (202) is arranged and deformable, and that by a device (188, 190) the Potential of the deformable part (198) below that of the amplifier (40, 92) is durable, so that when the deformable part (198) moves, the capacity changeable between the first conductive element (202) and the deformable part (198) is. 22. Circuit device according to claim 14 with a KathodenstaShl tube, characterized in that a Di dielectric (10) on the first conductive element (12) is arranged, the image on the cathode ray tube is visible through the dielectric (10). 23. Circuit device according to claim 22, characterized in that g e k e n n -z E i c h n e t that the dielectric (10) as an at least a part of the cathode ray tube covering plate or layer is formed. 24. Circuit device according to claim 22, characterized in that g e k e n n -z e i c h n e t that several conductive elements (12) on the side of the dielectric (10) are arranged, which faces the cathode ray tube, whereby with this in relation standing switching functions can be generated, and that by a decoder the positions forming the corresponding switches can be decoded. 25. Circuit device according to claim 24, characterized in that g e k e n n -z E i n e t that a computer is coupled to the cathode ray tube and the bodies is, whereby a touched point can be determined and / or recorded, and that a shield between the conductive element (12) and the cathode ray tube is arranged, through which the interaction with the cathode ray tube can be reduced is.