GB2180288A - Lock having optoelectronic coders - Google Patents

Description

SPECIFICATION Lock having optoelectronic coders The present invention related to a lock having optoelectronic coders.

In the following description, the term lock is used in the very broad sense ofthe word to designate a device having optoelectronic coders of a very original and simple design thanks to its physical nature. It grants a space or a machine exceptional protection against unauthorised access. Such security is due to the ability ofthe lockto work simultaneously in normal permissive mode, which is the mode of classical mechanical locks, and in conversational mode. This lock can receive instructions from outside in logical oranalo- gical form, by cable, by telephone or by radio.Thus, a vast area of application is opened in the field of protected access to a space or a machine, both in the building, automobile, electrical or electronic machinery industries, as well as in strong boxes, etc.. ., as the optoelectronic lock can offer simple, effective and often very original solutions to the problems raised. In many cases it enters into direct competition with magnetic card locks by its safety- cost price ratio.

The volume occupied by the lock, constructed in an integrated form, can be much less than the volume of a classical mechanical lock. Its cost price can become extremely advantageous as it is possible to manufac turethe larger part of the coders in series.

In accordance with the invention, the optoelectronic lock is essentially formed by a permissive coder or by a level transmitter permissive coder and/or by a word generator coder, and/or by a normal keyboard or two-key keyboard coder, or again by a modem, and by a optical key.

The permissive, permissive - level transmitter and word generator coders are optoelectronic coders formed by a network of photocouples which are created, on the one hand, by a single photoemitter or by a network of photoemitters working, for example, in the infra-red zone, and, on the other hand, by a network of photoreceivers, such as photodiodes or.

phototransistors, inter alia. Only the nature of the electrical circuit connecting the photoreceiversto one another defines the type of optoelectronic coder.

The permissive coder performs the permissive role of a classical mechanical lock, whereas the word generator coder allows the individualisation of an optical key from several keysforthe same lock, each key generating its own word.

The leveltranmsitter permissive coder is a permissive coder to which is associated a modulator which is a simple network and which makes it capable, on the one hand, of receiving a sequence of logical or analogical levels at its electrical input, and, on the other hand, oftransmitting these same levels, in the same order or in a different ordertowards the output.

A keyboard coder enables the generation of an external code in logical mode and which is applied to the input of the level transmitter. This exterior code may represent any instruction or simply express the user's knowledge of his own code generated by the key. To simplify the lockunittothe maximum, the use of a two-key keyboard coder is recommended, which thus makesthe unit more compact, more reliable and less onerous. It is evident that the two-key keyboard coder in accordance with the invention may advantageously replace a normal keyboard coder in many other uses. The keyboard coder may finally be replaced by a modem if it is wished to apply analogical levels to the level transmitter.

The purpose ofthe above coders isto enablethe construction of access protocols which are as complex as desired. This explains the exceptional security which an optoelectronic coder lock offers.

All problems regarding protection against unauthorised entry correspond to two broad categories of locks, i.e. single lock key locks, and locks for multiple individualised keys, and to each category of lock correspond specific functional organisations, which, once highlighted, facilitate the choice ofthe adapted structures.

In the case of a sinlge-key lock, the lock, considered as a permissive device, authorises an action by emitting a signal, which is a permissive signal, permitting the said action ofthe object commanded.

According to the installation conditions of material connections, such as cables, between the command mechanism formed by the lock and the object commanded, two functional structures can be distinguished, i.e. a structure with a connection protected from manipulations and a non-protected connection.

The first case concerns a compact lock, such as a classical mechanical lock, in which the transfer of the permissive signal authorising the displacement of the dead bolttakes place only inside the lock housing, and therefore protected from manipulations. The functional structure of such an optoelectronic lock in that case comprises a single permissive coder.

In the case of a non-protected connection, it could be possible, if special precautions are not taken, to authorise, indeed even to trigger the command of an action, by manipulating the connection, as for exam ple in the case ofthe command forstarting sup a vehicle. Infactit is possibleto start up a vehicle without a contact key by having access to the command wires.These manipulations can be avoided if the permissive signal is in a coded form. For this purpose, the functional structure has to be formed by a level transmitter permissive coder, and by a fixed word generator, both being controlled by a single key.

In the case of a single lock authorising an individualised command for multiple access, each individualised command permitting access to one elementfrom all the individualised elements, it is possible to carry outeithera direct command by individual code, ora command by individual verified code.

In the first case the individual code is generated by the the key itself, and the permissive coderauthorises or not its acceptance. The functional structure, in this case, is composed of a word transmitter permissive coder and a word generator coder or any word source.

The command by verified individual code is a use of the lock in conversational mode which correspondsto the usage mode of a credit card and its functional structure comprises a word transmitter permissive coder, aword generator coder and a word source outside the lock, such as a keyboard coderora modem.

All the coders and two examples of actual application are represented by the attached drawings in which: Figure 1 schematically presents the total structure of a lock in accordance with the invention, in the form of functional blocks; Figure 2 shows an example of possible design of an optoelectronic coder, the drawing having been simplified; Figure3 represents one ofthe possible aspects ofan optoelectronic key; Figure 4shows, in a simplified way, the sectional view of a key positioned in the lock; Figure is a schematic diagram of a logical optoelectronicAND circuit; Figure 6 is a schematic diagram of a logical optoelectronic NO - OR circuit; Figure 7 is a schematic diagram of a permissive optoelectroniccoder;; Figure 8 is a schematic diagram of a word generator optoelectronic coder; Figures9to 12 represent some examples of associations including a modulator network and a permissive coderto form a level transmitter permissive coder; Figure 13 represents an explicit example of a permissive logical level transmitter coder; Figure 14 represents a functional diagram of a two-key keyboard coder; Figure 15 represent aconcrete example of atwo-key keyboard in accordance with Figure 14, the successive logical levels being generated alternately, and Figure 16 represents an example of concrete application ofthe optoelectronic lock having a protected command for starting up a motor vehicle.

In accordance with the invention, Figure 1 ofthe attached drawings more particularly shows the total structure of a complete optoelectronic lock The permissive or word transmitter optical coders 1 and the word generator2 are constructed in the form of integral circuits,the optoelectrnnicelementsbeing laid on common rigid supports 1. The key 5 is introduced into the coder. Atthe end ofthe movement, it engages a micro-interrupter 3 thus establishing the electrical supply to the unit. A device 4 outside the lock such as a keyboard coder or a modem can provide an external codeforcontrolling indi viduafised access, which, in this case, is applied at the entry to the level transmitter.

An optoelectronic coder only differs from another coder bythe electrical structure of the networks of photoreceiverswhich form it, theirpresentation and their technical design being identical. Such an optoelectronic coder is essentially formed, as shown by Figure 2, by a group of photocouples, which, by way of example, may be constructed on two support boards 6-6' of rigid material. Thus, by integrated circuittechniques, for example, a networkofphoto- emittentdiodes7is deposited on one ofthe boards 6, whereas on the other support 6' is deposited a network of photodiodes or phototransistors7',the group constructed in this way working, for example, in the infra-red zone.The two networks are constructed in accordancewith the same arbitrary geometric arrangement, but remaining fixed forthe set coders.

Figure 2 represents such networks in accordance with a plane arrangement, which is the most advantageous because of its simplicity. The set of photoemittent diodes can be replace by a single source such as daylight or a laser source diffusing illumination over the set of photoreceivers.

The two support boards 6-6' are assembled facing one another so as to form photocouples. A space is provided between the two boards in which the optical key 5 is placed (Figure 4). The latter is perforated at precise points (Figure 3) to allowthe illumination of certain photoreceivers 7', whilst blocking the others, in accordance with the network of photoreceiver7'. If the optical key 5 corresponds to the electrical configuration ofthe coder, the said coder issues a level or a series of electrical levels at its outlet.

The permissive code coder is the fundamental element of the lock, owing to the fact that any process produced within the lock is under its control. Such a coder is based on pure optoelectronic logic circuits developed subsequent to the specialist doctorate thesis prepared by the inventor on the theme: "Analogical photodiode current sources P.l.N." (June 1975 Strasbourg). It concerns logic circuits contructed purely by photocouples. The permissive coder is a combination of two of the logical base circuits, which are represented by Figures Sand 6.

Figure 5 represents a logical AND circuit, and Figure 6 represents a logical NO-OR circuit.

By designating the i light source by L1, and in the case of multiple sources, such as a photo-emittent diode (LED), a laser source or daylight, by designating the corresponding photoreceiver, such as a photodiode ora phototransistor, receiving an illumination Ej, by D1,for example, the logical value S regarding the potential difference V5 attheterminals of the load R is connected to the illuminations Ej by: S = E1 x E2inthecastofanANDcircuit (Figure 5), and S = E3 x E4 = E3+ E4, in the case of a NO - OR circuit.

More generally we have, respectively: S=E1 x E2x.. . x En(ANDcircuit),and S = Ea + E2 + . . .+E(NO-ORcirnuifl for n photoreceivers, a single source of light, on the other hand, being sufficientto illuminate the group of photoreceivers.

The above equations demonstrate that all the photodiodes or phototransistors in series with the load R have to be lit; and inversely,thatallthe photodiodes in parallel withthe load have to remain in darkness in order fo have a high level at the terminals of the load R.

By replacing the additional resistance R5 of Figure 6 by photo receivers in series with the resistive load R of Figure 5, a permissive coder 1 is constructed in accordance with the schematical diagram of Figure 7.

The load may be resistive, self-inductive orcapaca- tive or of a more complex nature, and at its level a permissive signal may be obtained in the form of a current crossing it, or in the form of a potential difference at its terminals.

The network structure of such a coder is translated by the general logical equation: S = E1 xE2x. Ep X Ep+i X Ep+2 X. . . Ep+n If joust one of then photoreceivers is not in the lighting conditions defined by the above equation, the outlet is atthe low logical level, for example. The role ofthe optical key 5, placed between the light sources and the photoreceivers, is to seal the photoreceivers in parallel on the load R, so that they remain in darkness and to allow the ilumination ofthephotore- ceivers in series with the load R. This is made possible by the perforations on the key at the defined points.

If n is the total number of photoreceivers, the number of logical combinations C which the network allows according to Figure 7 is: C = 2".

Thus,when n = 20,C = 1,048,580, which illustrates the particular benefit represented by the permissive coder.

A micro-interrupter3 incorporated in the coder is actuated bythe key 5when it is completely introduced into the coder 1. Thus, in rest the coder does not consume any current, but, and particularly, at the introduction ofthe key 5, it is avoided that the transitory states sometimes become active, The indentification of the complete code is thus made only when the key 5 is well in place.

The roll of the word generator coder 2, the schematical diagram ofwhich is represented by Figure 8, is to generate a logical word from a perforated optical key 5, which defines the word, the structure ofthe electrical network being permanent.

Depending on whetherthe photoreceiver D is illuminated or not, the logical level attheterminals of its load R is low or high.A register, for example, with parallel input, transfers the set of these levels towards its series output. The originality ofthis coder 2 in relation to the classical optical reader, does not lie in the level ofthe network, but in the level ofthe reading mode, the reading being carried out in the direction of a plane delimited by the active surface ofthe key 5, and in which are situated photoreceivers, and not in the direction of an array as in the case of a classical optical reader. On the other hand, the use ofthis coder in the field ofthe lock, presents its second original aspect.

The optical key 5 can take any geometrical shape and be made of any material. In particular, it can occur in the form of a magnetic credit card. The total active surface ofthe key can be divided into separate funtional zones such as a zone where the perforations correspond only to the permissive coder 1 and a zone where the perforations correspond to the word generator coder 2. These zones can also be interleaved or merged. A zone having a special function may in its turn be divided into sub-zones intended for partial use ofthe completezone so asto simplifythe construction of locks additional to the main lock and of secondary importance. The sub-zone can have the same functional specificity or not as the zone which sub-tends it.

When considering the network of a permissive coder, it seems that, if the permissive code ofthe optical key is correct, a current I crosses the load R, and to this current corresponds a potential difference at the R terminals. This potential difference V5 can be modulated if the current I is moduiated.Forthis purpose, one only has to modulate the illumination of any one photoreceiver, orthe set of photoreceivers, by modulating the current of a photo-emittentsource or the set of photo-emittent sources. For this purpose, a series network 24 can be inserted according to Figures Sand 10, at the inputofwhich a command signal Ve is applied. Thesame applies if one ofthetwo photore ceiverbranches is inserted an analogue network 24 capable of modulating the current of the branch used, and if adequate command signals are applied to it (Figures 11 and 12).

Figure 13 represents, as a concrete example, a simple diagram of a permissive, logical level transmitter coder 1. In such a coder, the potential difference V5 can be directly proportional to the control signal VE, the coder then occurring as an anlogical level transmitter. On the other hand, if, as is the case of Figure 13, we have the equation: Vs = W. The level transmission can only occur if the optical code ofthe key 5, represented symbolicallyon Figure 13, is correct, so that the level transfer is only authorisedwith the use of the appropriate key.

Thetwo-key keyboard coder4 (Figures 14 and 15) is intended to replace a normal keyboard coder. This coder4 is intended for the use ofthe lock in conversational modeforthe purpose of identifying the owner ofthe key. Such a coder 4 has a simplified structurewhilst retaining a coding capacity compara bletothatofa normal keyboard.Such a coder is formed, fundamentally, by a logical level generator8, by a two-key keyboardS, 10, by a device 25 for materialising levels generated by8, by a logical network 27 for controlling these logical levels avail able atthe outletofthe generator8, and also buy a register 12 which stocks the chosen levels forming the keyword, the structure ofwhich depends on the order in which pressure is put on the keys Sand 10.A comparator 13 compares the word from the register 12 with the reference words contained in a word source 26 such as, for example, a set of registers.

Clearly the elements 12,13 and 26 can be part of a microprocessor, the element 26 being, for example, a MEM (ROM).Theset operates in thefollowing way: any pressure on oneofthetwo keys 9 and 10 provokes a change or not in the logical level ofthe generator output 8 according to a series of random or preestablished logical levels. The device 25 materialises these levels in an acoustical our visual form. On the nature ofthe level depends the selection of the key to be pressed 9, 10. One ofthe keys takes into consideration the level chosen fortheformation ofthe complete word, the other key eliminates the corresponding level. Every pressure simultaneously generates the following level atthe level generator outlet 8. Consideration or elimination are decidedatthe level ofthe logical network 27 depending on the key pressed as a function ofthe nature ofthe materialised level. All the logical levels considered are stored in the same order in the parallel series register 12 so as to be compared by the comparator 13 with the reference words contained in the word source 26. When the words compared coincide, the comparator issues a determined level signifying the acceptance of the coded word onthe keyboard. Thesimplestcase of level generation is that where the levels alternate with any pressure on one ofthetwo keys. In this case, the materialisation ofthe levels is superfluous and the coding ofthe work is simplified.This coding is expressed by two decimal numbers, for example 1 and 2, the number 1 signifying,for example, the acceptance ofthe level and corresponding to the key numbered 1, and the number2 signifying the elimina- tion ofthe same level and corresponding to the key numbered 2. The user has to knowthe decimal sequence,forexample 1 1212212fora word of eight successive levels and not know their significance. This means that, arriving in order atthe level generator outlet, here in the hypothesis of alternate levels, a bistable can perform this role, the 1 sot, 2nd, 4th and 7th levels are accepted in accordance with the abovementioned rule, the 3rd, 5th, 6th and 8th being refused.

The result of this is thatthe coded word stored in the register is a 4-bit word, since four levels are accepted and transmitted to the register. The first level when the keyboard and the lock are switched on must always bethe same initial level. If, for example, this first level, in the present case, is a low level and, taking into accountthefactthatthe levels atthe output of the generator 8 alternate, then the word in the memory is a word composed of successive levels LHHL which can be deduced by the table of correspondence below.

11212212 LHLHLHLH

LH H L The coding may be made more complex, without modifying electrical circuits of the coder4, by supplementing the two-key keyboard by additional dummy keys 14, 1 5, the number of which may be greater than two, connected or not to oneof the two principal keys 9 and 10. Thus, all the keys become active and allowthe code to be expressed by several numbers, although pressure on a dummy key 14,15 corres pongs to pressure on one ofthe main keys 9, 10.

Taking a 4-key keyboard, two of the keys are dummies, as an example, a number 1 to 4 can be associated to each key. Supposing that the keys ofthe even numbers and those ofthe odd numbers are connected electrically two to two,the result is that a code can be expressed in several ways, so that the following codes are equivalent: (a) 1121221-mainkeys9and 10 only (b) 1341243 (c) 3121421 with the dummy keys 14 and 15 Ofcourse,the user must not know the significance ofthe numbers, i.e.thewayin which the dummy keys 14 and 15 are connected inside the keyboard to main keys 9 and 10, as he only has the ciphered code, which informs him which keys are to be actuated in order to confirm his personal code.

The general functional structure of a keyboard coder isshown by Figure 14and a concrete example of application of a coder 4 associated to the optoelectro nic lock is represented by Figure 15.

Figure 16 is the explicit diagram given by way of example of an application ofthe lock having a level transmitter coder (CTN) in the automibile industry. It represents the starting command for a motor vehicle.

With the introduction ofthe optical key 5 into the lock, the interrupter 3 establishes the power supply to the electronic unit. The permissive coder, by means of the key 5, authorises the transmission from the inlet towards the outlet of the level transmitter coder of the word contained in the preprogrammed register 31 by authorising the transmission of successive levels to the rhythm ofthe clock 29. The parallel series register 12 accepts the word which the comparator 13 compares with the recorded word 26. When identity is established, the comparator 13 throws the bistable 30, which, in its turn, authorises starting (byturning the key) by means ofthe interrupter M. The iatter operation is, in fact, useless, but it is specified here so that the user does not lose the habit.It should be noted, on the one hand, thatthe real volume ofthe lock must not exceed the volume ofthe classical mechanical lock, whilst allowing other simultaneous protective measures and commands. Similarly the receiver part could occur in the form of a single integrated compact circuit having the dimensions of a DIL integrated circuit having 14 pins. On the other hand, the unit ensuresquasi-absolute protection of the car thanks to the burglar-proof optical coder, but also thanks two the factthatthe connecting wires between the lock and the receiver are electrically inactive and of no consequence to the short circuits which could occur exceptthe short circuit between the positive pole and the mass.The theft-proofing is practically infallible if the lines 19,20,21 and 22 remain inaccessible for undesirable manipulations. In this diagram, the num berofconnecting wires ABCD,which is four, is a minimum possible number, taking into consideration thefactthatthe connection ofthe mass E is performed by the body of the car. Given thatthe the currents transmitted by these wires are in the order of 10 mA, the connection may therefore be made with the help of a low diameterfourwire cable.

It should be noted that in the diagram of Figure 16, the register 31 is used as a reference word source, in orderto clarifythe operation ofthe set, but it is evident that the word generator optoelectronic coder may perform this role, whilst simplifying the same diagram. Thus the permissive code and the reference word are simultaneously generated by the same key.

Claims (10)

1. Electronic lock having codes, characterised in that it comprises an optoelectronic coder (1,2,4), a removable opitical key (5), and a microinterrupter (3) locked by this key when it is in place in the lock.

2. Lock accordingto Claim 1, characterised in that the coder (1) comprises a permissive coder, which is formed, on the one hand, by a resistive or inductive load or a load of a more complex physical nature, at the level ofwhich a signal is obtained intheform of a potential difference at its terminals or a current crossing it and, on the other hand, by a network of photoreceivers such as photodiodes, phototransistors, photoresistances, or others, several of which are branched in series between them and with the load, and the others ofwhich are branched in parallel between them and with the load, the set of photore ceivers being illuminated either buy a single source, or by several sources of illumination, and in that all the network is fed with current through the medium of a microinterrupter (3) which is an integral part of the permissive coder, and which is actuated by the complex introduction ofthe key (5) into the coder.

3. Lock according to anyone one of Claim 1 and2, characterised in that the coder is a level transmitted permissive coder, formed by a permissive coder to which is associated a modulatorcapable of modulat ingtheoutputsignal ofthecoder,acommandsignal being applied tothe input ofthe modulator and found in the same form at the output of the permissive coder.

4. Lock according to Claim 3, characterised in that themodulatorcomprisesatitsinputa command component,formed bya keyboard coder, or byan appropriate modem permitting it to receive external information by cable or by radio.

5. LockaccordingtoanyoneofClaimsl to3, characterised in that it comprises a word generator coder (2), formed by n photoreceivers (7') disposed in a plane (6'), opposite a common sourceofillumination or n photo-emitters (7) disposed in a parallel plane (6), the unit forming n photocouples, a perforated key (5) capable of being introduced between the photoemit ter(s) (7) and the photoreceivers (7') making certain photocouples active, determined by the perforations of the key, each photoreceiver (7') having its own load, in which it delivers a current if it is illuminated, the set of electronic levels at the terminals of the set of loads defining a logical word,the structure of which depends on the geometrical arrangement of the perforations ofthe key (5), and by a parallel-series register or a multiplexer having n inputs and an output allowing the series transfer ofthe word read in the direction of a plane or skew surface defined by the geometry ofthe key.

6. Lock according to Claim 1. characterised in that the coder comprises a two-key keyboard coder (4), formed on the one hand by a two-key keyboard (9, 10) having simple or multiple contacts, these two keys being associated or not to dummy keys (14,15) and on the other hand, by an electronic unit comprising a level generator (8), a visual or sound materialisation device (25), levels from the generator (8), a logical network (27) taking into consideration levels generated by the generator (8), as afunction of the commands transmitted by the keyboard, a register storing (12) successive levels taken into consideration, a reference word source (26), and a comparator (13) comparing the word stored in the register (12) with one ofthe reference words from the source (26) and issuing an impulse if there is coincidence of the two words compared.

7. Lock according to Claim 1, characterised in that the optical key (5) comprises a part having a flattened shape, cailed the active su rface, the role of which, when introduced into the lock, is to seal or not a defined set of photoreceivers forming part ofthe coder (1,2,4), this key being provided for this purpose with perforations ortranslucentzones distributed in the active surface in accordance with a determined geometry.

8. Local according to Claims 5 and 7, characterised in that the total active surface ofthe key is divided into functional zones, namely a zone where the perfora tions correspondtothe permissive coder (1) and a zone where the perforations correspond to the word generator, these zones capable of being overlapped.

9. Lock according to Claim 8, characterised in that a functional zone is divided into sub-zones intended fora partial useoftheentirezone, in locks supplementaryto a main lock, the sub-zone capable of having a functional specific character different from that of the entire zone of which it is part.

10. An electronic lock having codes substantially as herein before described with reference to and as shown in the accompanying drawings.