DE2833304A1 - KEY CONTROL SWITCH - Google Patents

Description

The invention relates to tactile control switches, i.e. switches, that depends on the change in a capacitive coupling between the "touched" plate and an adjacent one Address plate, the change is made by the approach of the finger of an operator against the "touched" Plate generated.

A typical touch button switch consists of a sheet of dielectric material with a first conductive sheet Layer that is applied to one side and a second and third conductive layer that are applied on the opposite side of the plate, overlapping the first conductive layer, so that said capacitive coupling can arise between the layers. On the second conductive Layer an interrogation signal is applied and the corresponding induced on the third conductive plate Output pulses are analyzed to determine whether the switch by the approach of a finger in the direction of the first conductive layer has been operated or not. The approach of the finger causes a decrease in the amplitude of the output signal, which can be used to initiate a control function.

There are also electroluminescent devices are known in which a phosphor layer between two plate-shaped electrodes are arranged so that they are affected by an electrical potential between the electrodes is excited and emits light that penetrates one of the electrodes and produces a visible indication. Electroluminescent devices are used in

809886/1015

Used in connection with electrical switches to indicate certain control functions. However, the electroluminescent devices and switches are independent of one another.
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The present invention provides a tactile control switch which is first and second conductive Has layers arranged on opposite sides of a dielectric plate in an overlapping manner are, furthermore, an electrical connection to the second layer to confirm that the switch has been actuated to be determined with an interrogation signal. A phosphor layer is connected to the second conductive layer in contact; which in turn is covered by an electrode will. The electrode has an input terminal for applying a lighting control signal. The dielectric Plate and the first and second conductive layers are made of a translucent one Material so that light from the phosphor layer can penetrate the other layers, if the latter is excited by a potential difference generated by the signals on the second conductive layer and the Electrode is generated.

With the invention, a push button control switch is thus combined with an electroluminescent device created that emits visible signals, each associated with the operation of the switch are. An operating element in the form of the second conductive Layer is used for both switching and lighting functions.

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The query signal can be used to control the switching and perform lighting functions at the same time. Alternatively, a signal that is separate from the query signal can also be used to generate the lighting function will. In any case, the interrogation signal or the signal separated therefrom is used to lower the phosphor To stimulate control of the lighting signal.

Several of the push button switches according to the invention can preferably arranged in an array, with the electrodes of a set of switches being a one-piece Element are and wherein the applied to the electrode lighting control signal in time correspondence with the input signal to the individual switches of the set.

Embodiments of the invention are based on the following the accompanying drawing, for example, described. Show in it:

Fig. 1 is a schematic exploded view of a

Push button control switch, and 30

2 shows a schematic block diagram of a plurality of pushbutton control switches arranged in field form according to Fig. 1, which are connected to a microcomputer.

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The tactile control switch, as shown in Fig. 1, consists of a dielectric plate G made of glass, a conductive layer A is applied to the front surface thereof is and two similar conductive layers B, C on their rear side, arranged lengthwise next to each other and layer A overlapping. Layer B is provided with an input connection SC, Layer C with one Output connection SW, so that the layer B with a Interrogation pulse can be applied in the layer C because of the capacitive coupling between the two layers B, C induce an output signal via layer A. When layer A is touched, the capacitive properties of the switch change, with the amplitude of the output signals falling and thus a control function in an external monitoring circuit that triggers with the connections SC and SW is connected. In this respect, the structure of the switch is known.

However, the switch still has an electroluminescent Device on, so that light emanating from an electrically excited phosphor P, through to the front the plate G arrives and can be seen by an operator. The conductive layers A, B and C. are designed so that they are translucent and are each applied to glass in the required shape or etched out of a conductive layer covering the glass. The connections SC and SW are preferably formed in one piece with the conductive layers B and C in one and the same manufacturing step,

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A mask M made of an electrically insulating material is then placed on the back of the plate G applied so that only the symbol-shaped area layer B remains free. As a symbol, for example, the capital letter "S" is shown in Fig. 1, where the Mask in the form of a layer with the capital letter "S" is shown separately. The mask is preferably M however, a coating applied to the plate G and the symbol figure is etched out of the layer, so that the underlying layer B is exposed in the corresponding area.

A phosphor layer P is applied to the rear surface of the plate G or at least to the area of the layer B, which bears the symbol and an electrode is brought into contact with the phosphor so that it covers the area of the Layer B, on which the symbol is located, covers.

To the electrode E an input line SL is connected to the electrode from an external monitoring circuit to load off with a lighting control signal, whereby the excitation of the phosphor P is controlled will. The phosphor P is excited when the potential difference between the layers B and the Electrode E, which is generated by the interrogation pulses and the lighting control signal, has a specific one Illumination threshold exceeds, usually the layer B applied with positive pulses via the input SC and the lighting control signal, which via the input connection SL passed to the electrode E. is either a grounded signal, which limits the potential through the phosphor so that this

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is not excited, or it is a negative signal that has a sufficiently large potential difference relative to the x ^ positive pulses results, so that the phosphor is excited and emits light accordingly. the Positive pulses can be used to query the state of the switch as well as the phosphor according to the control of the lighting control signal.

The mask M is preferably used to cover the area of electrical contact between layer B and the phosphor layer P so that a well-defined symbolic image is created to ensure that the Image of other components, such as connection SC, does not appear. Preferably they are Electrode E and the phosphor layer P in their size limited so that they do not overlap the conductive layer C, because this would create a capacitive coupling between the layers B and C, which with the normal switching function of the switch collides.

In Fig. 2 a 4x4 multiplex array of switches is shown, each of which is constructed similarly to FIG. 1, the input connections SC, SL and the output connections SW equipped with a monitoring circuit

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809886/1015

_ ₁₄ _ 28333Q4

are bound, which consists of a microcomputer F. the Switches are arranged in rows and columns, with the input connections SC of the four switches each Series with a common input connection SC1, SC2, SC3 and SC4 are connected and the output connections SW of the four switches in each row with a common one Output terminal SW1, SW2, SW3 and SW4, respectively.

The microcomputer F has an 8-bit input / output connection 1/01, with four outputs via a voltage amplifier IC1 are connected to the four input connections SC1 to SC4 of the switch panel and the four inputs via a buffer circuit IC2 with the output terminals SW1 to SW4 of the switch panel.

The microcomputer generates a series of square interrogation pulses with an amplitude of 5 V, which are transmitted by the Amplifier IC1 can be amplified into 50 V signals and 'to the input terminals SC1 to SC4 of the field reach. The resulting output signals at the output terminals SW1 to SW4 are sharp pulses as a result the capacitive nature of the push button switch. The rate of decay of these signals is, however, through the buffer circuit IC2, which has a high input impedance. The amplitude of an output signal is reduced, when a switch is operated and falls below a certain threshold set in the buffer circuit IC2 can be set so that this pulse is not used as an output pulse to the microcomputer is passed on. The output of a non-operated switch, however, causes a corresponding output pulse of the buffer circuit IC2

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to the microcomputer. The buffer circuit IC2 is designed so that its output pulses that are sent to the microcomputer are passed, have a substantially square pulse shape, with an amplitude and length similar to the output pulses of the microcomputer are. This allows the input and output pulses to be analyzed together in the microcomputer, to determine whether one of the switches on the switch panel has been actuated.

In an alternative embodiment, four comparators can also be used instead of the buffer circuit IC2 each having a first input from one of the output terminals SW1 to SW4 and a second input of a voltage divider which defines a limit potential for all comparators, the one level corresponds, which distinguishes between output signals from an actuated and non-actuated switch. An advantage of this arrangement is that when using one and the like bti T.quelle for the voltage divider and the interrogation pulses, a further variation in the supply voltage can be tolerated than when using the buffer circuit IC2.

The arrangement works as follows. The microcomputer F supplies four interrogation pulses to each of the

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Inputs SC1 to SC4 (in sequence). When the four switches interconnected with the input line a row have not been served, they then give one each time via the output circuits SW1 to SW4 Impulse when they are queried. However, if one of the switches has been operated, the passage becomes of a pulse to the output connection is prevented, which is connected to the corresponding row of switches is where the switch is located. Every time a column is queried, the microcomputer pays attention the absence of a pulse on any of the output connections to determine if the switch in question has been operated in this row of switches. The four interrogation pulses applied to each column therefore query the four switches in this column one after the other to determine whether the switches were actuated. Each column of switches is then queried in the same way.

When an actuated switch is identified, the microcomputer F preferably checks the identification before it initiates suitable further control steps. The verification is thereby achieved that the entire switch field is queried again as prescribed several times, whereby it should be determined whether a certain switch is still holding back the output pulse. The way of working each switch generates a unique identification code that, after its first generation is stored in the microcomputer. This code is then compared to the code that was during of the successive checking results. Suitable Control steps are only initiated if

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a certain number of successive comparisons results in agreement.

The microcomputer can identify a individual actuated pushbutton switches, the simultaneous actuation of two or more such pushbutton switches and use this condition to initiate further control steps.

In addition to generating interrogation pulses to determine the status of the switches, the microcomputer can also Generate lighting control signals in which the electrodes E of the switch are applied to control the lighting of each switch. This is achieved in that all electrodes E of the switch a row via the relevant input terminals SL1 to SL4 one after the other with a lighting control signal be applied. This is done in time with the impulses that are sent to the input terminals SC1 to SC4 are given so that the lighting of each switch can be controlled individually. The lighting control signals are received from the microcomputer generated in the required sequence at four outputs of the input / output connection 1/02 and.

are passed on to the connections SL1 to SL4 via the amplifier IC3. The electrodes E each Series are connected to one another via their input connections SL and to the corresponding connections SL1 to SL4.

The input pulses that are sent to the connections SC1 to SC4 in time-to-match with the lighting control signals to the connections SL1 to SL4

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can be interrogation pulses that are analyzed to see if any of the switches have been operated. Preferably, however, the pulses that are on the connections SC1 to SC4 are given independently of the query pulses generated and the microcomputer controls the querying of the actuated switches and the lighting of the switches separately from each other.

The microcomputer F has instructions which enable it to carry out the required successive output / input steps at one speed
perform the prescribed punctures is appropriate. An example of a suitable microcomputer is the type F-8 from Fairchild.

The switch panel shown in Fig. 2 preferably has a single dielectric plate G on which individual conductive layers A, B, C of the switches are applied. It is also advantageous when

such a uniform structure has a common
Provide electrode E for each row of switches, so
that only a single input connection SL is required for each row in order to connect them to a corresponding connection SL1 to SL4. This can easily be achieved in an arrangement according to FIG. 2 in that the layers B and C are arranged one above the other instead of side by side and a single electrode strip E extends along the row of layers B, whereby it does not overlap the layers C. FIG.

Although a 4x4 square switch panel has been shown, any symmetrical or non-symmetrical panel can be used of η groups of m switches each with m query input

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used, each with a corresponding Switch set are connected, which has a switch in each group, and furthermore with η query outputs, each of which is connected to all switches of a certain group and also to η lighting control inputs, each associated with all of the switches in a particular group.

The shown push button control switch and the field of push button control switches can be installed in a hermetically sealed housing. On the back of the dielectric Board G can also be a printed circuit board which contains the interface circuitry as the circuits IC1, IC2 and IC3.

According to a further aspect, the invention can also be provided that several push-button control switches in a field with η groups of m switches with each m query inputs are arranged, each with a corresponding sentence of the Schalι - ^^. connected is, each containing one switch from each group and furthermore with η query outputs, each with is connected to all switches of a specific group; a computer can handle the query inputs and outputs be connected in such a way that a query signal is applied to each of the inputs one after the other and the signals be analyzed after each application of the interrogation signal at the outputs to determine whether one the corresponding switch sets has been actuated.

In this embodiment of the invention, the feature of electroluminescence is not included. Every touch

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ORIGINAL

control switch is of known construction, but the switches are arranged and are arranged in the form of a field queried sequentially by a computer, as shown for example for a field of four groups each containing four switches as shown in FIG. When the characteristic of electroluminescence is omitted in the embodiment shown in FIG. 2, the voltage and current intensity of the Query pulses are reduced. When the input voltage is appropriately selected, the buffer circuit IC2 in the output line for the interrogation pulses can be omitted.

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Claims (15)

PATENT LAWYERS DR.KADOR & DR.KIAJNKER K 12 398 / 7S TI (GROUP SERVICES) LIMITED TI House, Five Ways Edgbaston Birmingham, B16 8SQ UK Touch control switch Claims 1 Λ Tactile control switch with first and second conductive layers overlapping one another on opposite sides of a dielectric plate, with an electrical connection of the second layer for use in detecting the actuation of the switch with an interrogation signal, characterized in that the switch continues a phosphor layer (P) which is in contact with the second conductive layer (B), an electrode (E) which covers the phosphor layer (P) and an input connection (SL) of the electrode (E) for applying a lighting control signal, wherein the dielectric plate (G) and the first and second conductive layers (A, B) are made of a transparent material so that light from the phosphor layer (P) can pass through these layers when the latter is excited by a potential difference caused by signals the second conductive layer (B) and the electrode (E) is generated. 809886/1015 ORIGINAL INSPECTED 2. Switch according to claim 1, characterized in that g e k e η η ze Lehnet that an electrically insulating hat layer (M) is arranged over the second layer (B) is, so that only the symbol-shaped area of the second Layer (B) is exposed, and the phosphor layer (P) is applied so that at least the symbol-shaped area the second layer (B) is covered. 3. Switch according to claim 1 or 2, characterized in that a third conductive Layer (C) is provided on the same side of the plate (G) on which the second conductive Layer (B) is located so that the second and third layers are each separate from the first Layer (A) opposite, that furthermore the third layer (C) has an electrical connection (SW; has, which together with the electrical connection (SC) of the second layer (B) serves to provide a Pressing the switch to determine that an interrogation signal is given up on one of the connections (SC, SL) and that a correspondingly induced signal is removed from the other connection (SL, SC) will. 4. Switch according to claim 3, characterized in that the electrode (E) rejects the third Layer (C) not covered. 5. Switch according to one of the preceding claims, characterized in that the electrical Connection (SC) of the second conductive layer (B) an input connection for applying an ab- 809886/1015 request signal to determine the actuation of the switch is. 6. Push button switch according to one of claims 1 to 5, woboi several of the switches are arranged together, characterized in that the switches are arranged in a field of η groups of m switches each with m query inputs (SC) and each of the inputs with a corresponding set of the Switch is connected, each containing a switch each group and further with η lighting control inputs (SL), each of which is connected to the electrodes (E) of all of the switches in a group and with a computer (F) which is connected in this way to the inputs (SC, SL) for querying and for lighting control is that certain selected switches are illuminated by the application of signals can. 7. switch panel according to claim 6, characterized in that the switches on a common dielectric plate (G) are attached and the electrodes (E) of the switches of each group of one single electrode are formed. 8. Switch panel according to claim 6 or 7 in connection with claim 3, characterized in that the switch field η has query outputs (SW), which are each connected to all of the switches of a certain group that the computer (F) with the Query outputs (SW) is connected and works like this, that the query inputs (SC) one after the other with a 809886/1015 Query signal are applied and the signals after each application of a query signal to the Query outputs (SW) are analyzed to determine whether one of the corresponding switch sets has been actuated. 9. Switch according to claim 3 or 4, wherein a plurality of switches are arranged in the form of a field, characterized in that the switches are a field of η groups of always m switches with m questionexngganges (SC), each of which is connected to a corresponding switch set, the one switch of each group contains and furthermore with η query outputs (SW), each of which is concerned with all of the switches of a Group is connected and with a computer (F), which is connected to the query inputs (SC) and the outputs (SW) is connected so that a query signal can be applied to all inputs (SC) one after the other and the signals at the outputs (SW) are analyzed after each application of an interrogation signal can, to determine whether one of the specific Switch sets actuated x-jurde » 10 = switch panel according to claim 3 or 9 _t characterized in that the query signal is given to each of the query inputs (SC) several times during each query cycle, so that the computer (F) detects the status of each switch group several times and only responds if the same signal pattern _0, which corresponds to a control function, appears each time at the query outputs CSW) » © 08816/1011 11. Switch panel according to one of claims 8 to 1O, characterized in that the interrogation signal is a pulse signal so that the interrogation output (SW) each of the switches generates an output pulse with a reduced amplitude when it is actuated, and each query output is connected to the computer via a circuit (IC2) which at Applying a query output pulse to the computer (F) only then passes when the amplitude of the interrogation pulse is above a certain threshold, which is the lower limit of the amplitude of a non-actuated Switch outgoing query pulse corresponds. 12. Switch panel made up of several push-button control switches, characterized in that the switches are arranged in a field of η groups, each with m switches with m query inputs (SC), whose each connected to a respective set of switches including one switch from each group with η query outputs (SW), each of which with all Switches of a certain group is connected and with a computer (F), which is connected to the query inputs (SC) and outputs (SW) is connected, so that the inputs (SC) one after the other with an interrogation signal can be applied and the signals at the outputs (SW) after each application with a Interrogation signals can be analyzed to determine whether one of the switches of a particular switch set has been actuated. 13. .Switch panel according to claim 12, characterized in that each switch is first 809886/1015 - 6 - £ ο 4 α- α U Κι and second conductive layers (A, B) which arranged on opposite sides of a dielectric plate (G) in an overlapping manner are, furthermore, an electrical connection (SC) to the second layer (B) in order to operate the switch by means of an interrogation signal to determine with a phosphor layer (P) that is connected to the second conductive layer (B) is in contact, an electrode (E) overlaid on the phosphor layer (P) and an input connection (SL) for the electrode (E) to apply a lighting control signal to the electrode, wherein the dielectric plate (G) and the first and second conductive layers (A, B) consist of a translucent material so that light from the phosphor layer passes through the layers can penetrate if the latter is excited by a potential difference that is generated by the Signals to the second conductive layer (B) and the electrode is generated.
20th 14. Switch panel according to claim 13, characterized in that η lighting control inputs (SL) are present, each of which is connected to the electrodes (E) of all switches in a group _and that the computer (F) with the query and lighting control inputs (SC, SL) is connected, so that individual selected switches are illuminated by the signals applied to the inputs can.
30th 15. Switch panel according to one of claims 12 to 14, characterized characterized in that an interrogation signal, m each of the interrogation inputs (SC) during each 809886/1015 2B33304 Query cycle is applied several times, so that the Computer detects the status of each set of switches several times and only responds to the Interrogation outputs (SW) each time the same signal pattern results in = _ra ο