ELECTRIC SWITCH DEVICE WITH AN ACTUATOR KEY COMPRISING A NON-GALVANICALLY COUPLED INDICATOR DISPLAY

Abstract: An electric switch device having a fixed base body (10) and an actuator key (7) that is arranged movably relative to said base body (10). A non-galvanically coupled indicator display (1) is arranged within the actuator key (7). Within the base body (10) a radiation source (4), preferably a light emitting diode (18) is provided for, which is actuated by coded pulses, and is coupled non-galvanically with a means (3) for converting radiation into electric signals, preferably with a photocell (19) that is arranged within the actuator key (7). Output voltage generated by said photocell (19) is applied both to a rectifier and to a processor unit (2) that are both arranged within the actuator key (7). The indicator display (1), preferably liquid crystal display (LCD) is activated by the processor unit (2) while the rectifier provides supply voltage both for the processor unit (2) and for the indicator display (1). Thus, the actuator key (7) is merely non-galvanically coupled with the fixed base body (10) and a large variety of symbols such as geometric patterns, characters and the like according to coded pulses imposed may be visually displayed by using one and the same indicator display (1).

Description: Electric switch device with an actuator key comprising a non-galvanically coupled indicator display Technical field. Tlie invention relates to an electric switch device comprising a switching πeωber rr nged between a fixed base body and an actuator key that is πovable relative to said base body, said actuator key contain¬ ing a non-galvanically coupled indicator display. Electric switches capable of indicating their function, their state of activation or even the necess of being actuated on the switch itself or on a well visible part thereof displaying selected ones o a large variety of known signs or symbols such as figu¬ rative patterns or alphanumeric characters are in measuring instruments, computer peripheries, typewrite and in many other types of equipment widely in use. In εoπe cases changeability of said signs or symbols applied on one and the sane switch may also be require " With typewriters, e. g. having interchangeable rotary heads for typing texts written in different kin of script, such as in Latin, in Cyrillic or in Greek letters, etc. by turn, it is desirable to have a key¬ board equipped with keys where the letters and charac¬ ters indicated thereon are changeable in accordance the particular rotary head which is just in use. " Kith, computer peripheries dedicated keyboards are frequently used wherein the keyboard function iε to be changed from one mode of operation to another by actuating a specific key button designed for that purpose. Further examples for the wide range of application are switches, push buttons and the like as frequently used in all kinds of electronic equip¬ ment and in a large number of instruments wherein it is preferred or even necessary to provide for a visual indication of their current state of activation e. g. by displaying certain symbols or inscriptions stating their particular mode of operation. Backi-rrouπd Art Hitherto several types of indicators associat ed with electric switches have become well known. Light effect indication has prooved to be the simplest way by using a light source for which today.,, mostly if not exclusively a light emitting diode (LED) is used that is arranged within the actuating member of the switch. This type of known indicators is capable of signalling two characteristic states of a switch. One of said states can be e. g. information about the switch being activated or rather about the acute necessity for the switch to be actuated soon for some particular.purpose. " With one known make of rotary " head typewriter of the kind as mentioned above the keyboard comprising a plurality of switches as individual keys is covered by a mask made of thin elastic sheet material, pre¬ ferably rubber, said mask bearing the letters and characters in accordance with the particular rotary head fitted for typing the required kind of text. " When changing the rotary head for another one for doing a different kind of script, indication change of the keys i. e. of the switches is performed by replacing the rubber sheet mask of the keyboard by O another sheet bearing indications that belong to the new rotary head. This known mode of changing indication is not at all convenient. The thin rubber sheet mask is liable to damage. Several different masks are to be kept in store at hand. Service life of the masks is rather limited since thin rubber she are not resistant to ageing and to wear. According to another well-known technique, the individual keys of a keyboard bear a plurality of indications, i. e. signs, symbols, letters and/or characters simultaneously. In one particular mode of operation of the device in question is always only a pro-selected one of the indications per key (or switc of live relevance. Such indications are widely in use with multi-f nction push keys and switches ' of pocket and table calculators too. Tills type of multiple indication is associated with a number of particular dravjbacks. The indication applied by printing, gravin or in any other way can only be rather small in size. Another disadvantage is that the particular indicat¬ ion of having been pre-selected and thus, of temporar relevance must be kept and stored in mind. Thus, per¬ manent caution and care are necessary during work in order to avoid mistakes or malf nction. Electric switch devices having actuator keys comprising an indicator display capable of displaying a number of different symbols or signs on its visible surface without mechanical structures and component parts and having a significantly long service life together with a remarkable wear resistance have not become available so far. Disclosure of the Invention An object of the present invention is to provide an electric switch device having an actuator key comprising a non-galvanically coupled indicator disρl ? capable of displaying a number of different symbols, letters, characters or of short inscriptε merely electronically on one an the same display while long service life and high reliability of the switch device are maintained simultaneously. The above and other objects have been achieved by the provision of an improved new electric switch device of the kind as mentioned and described in the introductory part of the present speci ication wherein the invention lies in the new switch having a radiation source within the base bod}' and means for converting radiation into electric signals, said mean being arranged within the actuator key. The radiation source is in connection with a digital signal source while an output of said means for converting radiatio into electric signals is connected both, to a rectifi and to a processox* unit the output of which is in tur connected to the indicator display. Supply voltage inputs of both the processor unit and the indicator display are in connection with the output of the rectifier. In a preferred embodiment of the electric switch device according to the invention a light ' emitting diode (LED) is applied as radiation εourcg while as means for converting radiation into electric signals a photocell is provided for. Brief Description of the Drawings Fox* more accurate and better understanding, the invention will hereinafter be more particularly described with reference to the attached dra ings, in which, by way of example only, and with no limitin effect to the scope of claim Fig. 1 shows a schematic picture of a possi preferred embodiment of an electric switch device according. to the invention designed by way of exampl as a slide switch with an actuator key movable in a direction that is perpendicular to the plane of the drawing sheet, Fig. 2 indicates the electrical structure o the slide switch as shown in Fig. 1 schematically, Fig. 3 shows a more detailed circuit diagra of the electrical structure of the switch device in question, and Fig. indicates pulse pattern diagrams whi show the function and will be referred to in the following detailed description of the operation of the device as shown diagraraatically. in Fig. 3. Mode for Carrying out the Invention A preferred embodiment of the electric switc device according to the invention designed and constr ed as a slide switch is schematically shown in Fig. 1 of the attached drawing. The εi-Jitch device consists of a fixed base body 10 and of an actuator key 7 whic is εlidable guided in directions that are perpendicul to the sheet of the drawing between guide slots 8 of the base body 10. The latter is secured to a frame of an equipment (not shown) the switch device in question is applied to. The switch device as shown in Fig. 1 is to be actuated by sliding the actuator key 7 into different positions which may bo two or more in number. The base body 10 is equipped with a radiation source 4 preferably with a light source. However, the radiation source 4 n y be of any other kind, e. g. a source for generating electric or magnet field instead. The actuator key 7 provides or the electric contacts that are foreseen to its particular positions and it indicates simultaneously by displaying data, signs or figurative patterns that are characteristic for its cur-rent state of activation, the deed of a particular switching operation. Switching is performed by a signal transmitting member 5 arranged at the botto part of a housing 9 of the actuator key .7. said member being capable of transmitting radiation emitted b' the x^adiation source 4. In case of light radiation, as a signal transmitting member a light conductor or fibre optics known per se may be applied. For transmit magnetic radiation any soft-magnetic conductor while for that of electric radiation a simple electrical conductor can be used. At a location remote from the radiation source 4 - * - radiation detector 6 is secured to the base body 10. Upon sliding the actuator key 7 into activat switching position the signal transmitting member is moved into the neax- proximity of both the radiation source 4 and the radiation detector 6. Hence, a coupli is established between said component parts via signal transmitting member ? said coupling resulting in a significant change in the level of the output signal of the radiation detector 6. The change of the output signal level may be directly utilised for OMPI actuating an electric circuit to be switched. In case of light radiation, as radiation detector 6 a photodiode, phototransistor, photocell or a photo- resistor may equally be used. 17atuχ- , ally enough, any other kind of photoelectric inverter or coder may also be applied for said purpose. For indicating magnetic radiation e. g. an inductive coil or a Hall-generator while for the indication of electric field the armatur of a condensator may be used. Switching- may also be performed and establi in any other well known non-galvanic manner that will not be dealt with in detail within the present specifi ion- since these techniques are outside the scope of the present invention and are also quite obvious to those duly skilled in the art. As already mentioned earlier, the actuator key 7 of the proposed new switching device is equipped with a non-galvanically coupled indicator display 1 which is arranged on the top surface of the housing 3 * and is covered by a transparent cover plate 11. Prefer a liquid crystal display (LCD) is applied that is arranged on a support plate 12 which is secured to¬ gether with the indicator display 1 and the cover plate 11 to the housing 9, prefex^ably by an adhesive seal along the edges. The assembly consisting of support plate 12, of indicator display 1 and of cover plate 11 is held in position by a flange extending over the vex'tical wall partitions of housing S . In the bottom part of housing 9 opposite to the radiation source 4 an aperture is provided for in which a suitable means 3 for converting radiat¬ ion into electric signals is situated, .lien using light radiation, said means 3 for converting same into olectx-'ic signals is preferably a photocell genorεit electric voltage at its output upon receiving light. T?ιthin the pxOferx-cd embodiment shown in Fig. 1 said means 3 for converting radiation into electric signals and said signal " transmitting member 5 are arranged an positioned relative to each other in a manner that the beam of radiation directed towards means 3 is only partially intersected and thus, screened by said transmitting member allowing thereby a substanti larger quantity of the radiation energy to arrive at said means 3 and thus, to be converted into electric signals by the latter. Onto the inner surface of a bottom part of the housing 9 -** base plate 13 s secured which in turn, serves as a support member both fo^ the means 3 fox- converting radiation into electric signals that is secured to the lower surface of base- late 13 and or a processor unit 2 which is embedded in the upper surface of the same. Base plate 3 is provided with a wiring preferably with one of the printed circui type, for galvanically connecting the processor unit 2 to said means 3 for converting radiation into electric signals and also or connecting, processor unit 2 to the Indicator display 1 via connecting wires 14. Fig. 2 shows the electric structure of the electric switch device according to Fig. 1 ' in a schema- tic, partly axonometx-ic manner as a block diagram. The radiation source 4 is controlled by a signal source 17 which generates preferably digital signals that are coded in accordance with the symbols, patterns and/or characters to be displayed for indicating a current function or state of the switch. The same coded signals may be used for performing the switching operation itself, as mentioned earlier. For doing so, the coded signal is led via ra.diation source 4 and signal transmitting member 5 to the radiation detector when the actuator key 7 is moved into its activated position. In accordance with the plurality of codes applied, by means of a decoder (not shown) that is connected to the output of the radiation detector 6, an adequate plurality of connection patterns i. e. switching states can be generated and maintained. An output of the means 3 fox* converting radi ion into electric signals is connected via diode 15 to a condensator 16. Diode 1 aα condensator 16 to- gether provide for a rectifier whereby at the condens 16 a x-ectified direct voltage pulse pattern of voltage pulses that are introduced at said output of said mean 3 for converting radiation into electric signals is presented. In addition, said output of means 3 is also in connection with an input of the processor unit 2 for decoding and or activating the indicator dis¬ play 1 connected thereto in a manner so as to display a symbol, sign, patter 'or character that is defined by the current code that is just introduced to the radiation source 4. The output of the rectifier, practically presented by the two armature clamps of the condensato 16, is connected to supply voltage inputs of both the processor unit 2 and the indicator display 1. Thus, energy supply both for the indicator display 1 and for the processor unit 2 is met from the energy of radiation and no separate wiring for voltage supply to said units is needed. Fig. 3 shows a detailed circuit diagraπ of the structure according to Fig. 2 while operation and function of the circuit will be described in the follo ing with additional reference to Fig. 4 indicating different pulse patterns for more detailed expl εi ion OMPl - -1 C - T/ithin the embodiment of the electric switch device according to the invention as shown in Figures 3 and 4 a light emitting diode (LED) 1S is used as radiation source. Accordingly, as means for converting radiation into electric signals a photo¬ cell 19 is applied, the output of which is connected to a recti ier formed by the diode 15 and the con¬ densator 16, and ' also to a Schmitt-trigger 20 that forms the input of the processor unit 2. The latter ι σ comprises further a monoflop 21 , a- shi t register 22 a display driver 23 and an oscillator 24. The out¬ put of the Schmitt-tx-igger 20 is connected both to the input of the monoflop 21 and to the series data input of the shift register 22. An inverting output 15 of the monoflop 21 is connected to the clock input of the shift register 22. The outputs of the shift register 22 in turn are connected to data, inputs of a display driver 23 known per se, particularly of a liquid crystal dis- 20 pla-y driver having an oscillator input which the output of an oscillator 24 is connected to. Outputs of the display driver 23 are, in turn, connected to the inputs of the liquid crystal type indicator dis¬ play 1 in a manner knovin per se. 5 Pulse patterns shown in Fig. 4 will help to fully understand function aud operation of the circu indicated in Fig. 3« From a signal source not shown in Fig. 3 j coded pulses A are introduced to the ligh emitting diode 1 S which is emitting light pulses X 30 accordingly. Since the rate of transmission of the light emitting diode 1o is limited, the light pulses are slightly distorted. Arriving at photocell 19 } light pulses X generate voltage pulses 3 while the pulse pattern is fux-ther distorted. At the conden¬ sator lβ a filtered D.C. voltage C will appear that is introduced as supply voltage into the Schraitt- tx-igger 20, the monoflop 21 , the shift register 22, to the display driver 23 and also into the oscillato 24. " While passing the Sehiaitt-trigger 20, voltage pulses B will be refreshed, and at the trigger outpu pulses appear that ax-e substantially identical wit coded pulses A though they are slightly delayed with respect to the latter. The monoflop 21 is activated by the descending rear edges of the pulses D, and at. the inverting output Q of the monoflop 21 appear pul E of constant duration that are introduced to the clock input of the shift register 22.- Comparing pulse E and pulses D it will be appearent that data being currently given to the εcries data input of the shift i-egister 22 will be introduced into the latter upon the ascending edges of pulses E. Fig. 4 shows that simultaneously with the ascending edge of the first pulse E, pulse D is at its high logical level while pulse D is at its low logical level when the aεcendin edge of the second pulse E appears. Hence, already decoded pulse width modulated coded pulses A will be introduced into the shift register 22, and the decode pulse will appear at parallel outputs of the shift register 22 onl , a ter the series code is ully introduced. It will be appearent to experts duly skilled in the art that also embodiments of the circuit structure other than shown as a particular example in Fig. 3 ^ be designed and used. Depending from the coding system chosen the circuit structure may show significant alterations. It nay also be of advantage to integrate at least some of the circuit units into one single integrated circuit (lC). The scope of the invention is not at all affected by simultaneous application of two or more light emitting diodes 1S. Alternatively, instead of a single photo- cell 19, a. plurality of cells connected in series may be applied in order to achieve higher voltage. For diode 1 the use of a diode of the low drop-out voltage type may be of advantage. Lacking friction contacts, the electric switch device according to the present invention is of extremely high reliability. It can be used within a wide range of applications such as in multi-f nction keyboards of pocket and table calculators and the lilce in particular.

Claims: Claims 1. An electric switch device comprising a switching member arranged between a fixed base body and an actuator key that is movable relative to said base body , said actuator key containing a non-galva¬ nically coupled indicator display, said electric switch device being c h a r a c t e r i a e d in having a radiation source (4) within said base body ■ (10) and means- (3) for converting radiation into ' electric signals, said means (3) being arranged withi said actuator key (7), said radiation source (4) bein in connection with a digital signal source (17) while an output of said means (3) for converting radiation into electric signals is connected both to a rectifie and to a processor unit (2) the output of which is connected to said indicator display (1 ), and supply voltage inputs of both the processor unit (2) and the indicator display (1 ) are connected to the output of said rectifier. 2. An electric switch device as claimed in Claim 1 , c h a r a c t e r i z e d in having at leas .one light emitting diode (LED,- 18) as radiation source (4) while as said means (3) for converting radiation into electric signals at least one photocell (19) is provided for. ^- r ^_oM ■ " ■"■"

Inventors: DAVID GABOR, MEROE LASZLO, SZATMARI FERENC, DAVID, GABOR, MEROE, LASZLO, SZATMARI, FERENC
Applicants: GABOR DAVID, MEROE LASZLO, SZATMARI FERENC, DAVID, GABOR, MEROE, LASZLO, SZATMARI, FERENC
Application year: 1983
Main classification: G06F3
IPC codes: G06F3, H01H9, H03K17