EP0816601A2

EP0816601A2 - Optoelectronic lock with optical guides

Info

Publication number: EP0816601A2
Application number: EP97670003A
Authority: EP
Inventors: Paulo Joaquim Neves Dos Santos
Original assignee: Individual
Current assignee: Neves dos Santos Paulo Joaquim
Priority date: 1996-07-03
Filing date: 1997-06-06
Publication date: 1998-01-07
Anticipated expiration: 2017-06-06
Also published as: EP0816601B1; PT101890A; DE69721638D1; EP0816601A3; PT101890B

Abstract

The present invention is an optoelectronic lock using optical guides. It is designed to prevent access to areas, vehicles and machines.

It basically consists of a lock cylinder (24), normally located in the object to be protected, an optoelectronic module (12), one or more optical guide collectors (9), a set of optical guides (8) assembled in a cable (11), a source of electromagnetic radiation (6) and one or more keys (25).

The lock cylinder (24) incorporates a lock-identifier (1) with N₂ cross keyholes (7), each of which contains the tip of an optical guide (8).

The key (25) is fitted with a key-identifier (2), the shape and dimensions of which are perfectly adapted to those of the lock-identifier (1), and which have a longitudinal keyhole (4) from which a number of radial keyholes (3) branch off; the latter are positioned in such a way as to coincide with some of the cross keyholes (7). The longitudinal keyhole (4) contains the optical guide (82) which branches off through the radial keyholes (3) to form the optical guides (83).

Description

Technical nature of the invention:

The present invention is an optoelectronic lock which uses optical guides. It is designed to protect access to areas, vehicles and machines and is specially suitable for uses requiring high degrees of security.

Description of previous techniques:

In efforts to improve upon the security provided by conventional mechanical locks, electronic locks and security systems - especially those using optoelectronic technology - have in recent years undergone constant advances.

The optoelectronic locks and security systems currently in existence can basically be grouped into three different categories, all of which incorporate a lock cylinder fitted with one or more photoelectronic pairs and operate by means of a (usually remote) electronic circuit.

Each photoelectronic pair operates by means of a light-emitting diode positioned on one side of the keyhole. On the opposite side is a photodetector. When the key is introduced into the lock, the beam of light between the LED and sensor is broken.

The first type of lock, a description of which may be found in European Patent Application no. 84106299 by Naoyoki, Sugimoto, operates by means of a linear arrangement of various photoelectronic couples whose LEDs and photodetectors are positioned as described above.

The second type differs from the first principally in that the photoelectronic couples are usually arranged on a plane position, as proposed in European Patent Application no 85440011 by Radosavljevic, Milenko. Both types operate by means of a key with perforations in certain places which correspond to the arrangement of the photoelectronic couples. When inserted in the lock, the key allows some photodetectors to light up while covering others.

The electronic circuit then interprets the configuration of lit and unlit photodetectors to decide whether the key introduced is the correct one or not.

The third type of optoelectronic lock adopts a different approach, as described in International Patent Application PCT/US88/03345 by Pinnow, Douglas. This type operates by means of a single photoelectronic couple which electronically reads the contours of a conventional key.

The first and third type of locks nevertheless have the disadvantage of allowing only a very small number of combinations, i.e. of the different keys which can be made for a certain lock. This is due to the fact that the number of photoelectronic couples which can be fitted in a lock cylinder in a linear arrangement is necessarily very limited; similarly, the number of different contoured parts which one key can possess is also limited.

Furthermore, all three lock types use keys which are easily reproduced. And in many cases it is possible to circumvent the locking system simply by manipulating the electrical connections in the interior of the lock cylinder.

The third lock type has the added disadvantage of requiring a highly complex electronic circuit which is difficult to calibrate and requires a microprocessor. This makes it prone to malfunctions and also reduces the security : price ratio.

The above observations lead us to appreciate the need for an optoelectronic lock which allows far greater security than that offered by those which currently exist. Such security involves the use of keys which are more difficult to reproduce, a system allowing a greater number of combinations and the avoidance of electrical wires in the lock cylinder itself, since such locks can be opened without the key.

The advantages of the new lock:

The new lock overcomes the disadvantages and inconveniences of the optoelectronic security systems and locks currently in use by means of optical guides fitted in the lock cylinder and its connection to a remote optoelectronic circuit, and furthermore by the use of another device which we shall designate as an optical guide "collector" which has the following advantages:

Absence of electrical contacts inside the lock cylinder, which make it easy to "jump" the lock mechanism,
Use of keys which are difficult to reproduce;
Absolute flexibility of the format of the keyhole/slot in which the key is introduced;
Lock cylinders which, for the same dimensions, allow a far greater number of combinations;
The number of photodetectors required for such a large number of combinations is much smaller than it would be with previously-existing systems thanks to the use of the aforementioned optical guide collector

A brief description of the diagrams:

Fig. 1A is a schematic illustration of the principal components of the lock and their interconnection;

Fig. 1B is a simplified longitudinal section of a key-identifier inserted into a lock-identifier, both incorporating respectively in the radial holes (3) and cross holes (7), lenses of variable refractive indices;

Fig. 2A is a frontal view of a lock cylinder fitted with an octagonal hole and incorporating a shutter and pin latches;

Fig. 2B shows a cross section of the above lock cylinder;

Fig. 2C shows the same lock cylinder in longitudinal section;

Fig. 3A shows a top view of a key for the lock cylinder shown in figs. 2A, 2B and 2C;

Fig. 3B shows a longitudinal section of the same key;

Fig. 4 is a simplified illustration of a optical coupler/combiner fitted with lenses of variable refractive indices;

Fig. 5A is a simplified illustration of the longitudinal section of an optical guide collector using biconvex spherical lenses and with a built-in photodetector;

Fig. 5B illustrates an optoelectronic waveguide coupler/combiner, which we shall designate as an optoelectronic interferometric combiner;

Fig. 5C shows a set of optoelectronic waveguide couplers/combiners interconnected by optical waveguides in a tree configuration and using a star-type optoelectronic waveguide coupler/combiner;

Fig. 5D is a schematic illustration of the side view of an optical waveguide collector fitted with four star-type optical waveguide couplers/combiners;

Fig. 6A shows a longitudinal section of a lock cylinder of the flat variety of the present invention;

Fig. 6B shows the longitudinal section of a key for the lock cylinder illustrated in fig. 6A;

Figs. 7A and 7B show frontal views of the above lock cylinder and key.

Detailed description of the basic configuration:

The present lock basically comprises a lock cylinder (24), normally fitted to the object to be protected, a remote optoelectronic module (12), a set of optical guides (8), usually grouped by one or two wires linking the lock cylinder (24) to one or more optical guide collectors (9) and the optoelectronic module (12), and one or more keys (25).

The principal component of the lock cylinder (24) is a device which we shall designate a lock-identifier (1). This differs from lock to lock and is basically, as fig. 1A shows, cylindrical or prism-shaped. It can be made of steel, another metal or many other materials or combinations of materials. This lock-identifier (1) has a lengthwise hole which can be square, rectangular, circular or hexagonal (or other) in section and is the hole (16) in which the key (25), or part of the key, is inserted, except for the flat variety of the present lock, which has a different keyhole type. The lock-identifier (1) is also fitted with a series of N₂ cross keyholes (7) (N₂ being any whole number greater than zero) arranged either in a pattern or at random and different for each lock-identifier, each of which perforates the keyholes from the external surface to the aforementioned keyhole (16).

Each cross keyhole is positioned in a way which can generally be defined as perpendicular to the plane of the internal surface of the keyhole which they perforate. Thus if the keyhole (16) is rectangular in section each cross keyhole (7) will lie perpendicular to the plane which it perforates. The cross keyholes are normally circular in section with a diameter ranging from two to five millimetres.

In each cross keyhole (7) is the end of on optical guide (8), the other end of which is connected to an optoelectronic device (10) or optical guide collector (9) (see fig. 1A). Optoelectronic devices (10) (e.g. photodiodes, phototransistors, photoresistors etc.) convert optical (luminous) signals into electric signals. We shall refer to these simply as photodetectors. They are normally incorporated into the optoelectronic module (12). In certain versions, each photodetector is associated to an electrical circuit which pre-amplifies the electrical signals produced.

The optical guide collector(s) (9) is (are) optical or electro-optical device(s) which combine in a single output - normally an optical guide - the electromagnetic radiation produced by anv of the optical guides (8) connected to the input.

They may be positioned in the lock cylinder (24), the optoelectronic module (12) or at any intermediate point between the two. Usually only one optical guide collector (9) is used per lock.

As for the key (25), this incorporates a component which we shall designate as a key-identifier (2). The key-identifier (2) is of a shape and dimensions which allow it to be neatly inserted into the keyhole (16). It is normally made of material(s) similar to those used for the lock-identifier (1) and has a longitudinal keyhole (4) which does not generally span the length of the key.

The longitudinal keyhole (4) intercepts a series of N₁ radial keyholes (3) in the key-identifier (2) which are generally arranged so as to be perpendicular to the plane of the surface which they perforate.

These radial keyholes (3) are identical in format to the cross keyholes (7) and have a diameter which is equal to or slightly less than the latter. Their number N₁ is, in the basic version, smaller than the number N₂ of the aforementioned cross keyholes (7) (often half or less than half the number).

The radial keyholes (3) are positioned on the surface of the key-identifier (2) in such a way that when the key-identifier is inserted fully and correctly into the lock-identifier (1) for which it was made, its radial keyholes will coincide with some of the cross keyholes (7) of the latter. Thus, for example, if N₁ = eight and N₂ = sixteen, the key (25) belonging to a certain lock will in these conditions incorporate a key-identifier (2) with eight radial keyholes (3), which will coincide with eight of the sixteen cross keyholes (7) of the lock-identifier (1) of the corresponding lock (when the key (25 ) is correctly inserted).

The N₁ cross keyholes (7) which coincide with the N₁ radial keyholes (3) of the correct key-identifier (2) are those whose optical guides (8) are connected directly and individually to photodetectors (10), while the remaining N₂-N₁ cross keyholes (7) are those whose optical guides (8) are connected to the inputs of the optical guide collector(s) (9).

Each radial keyhole (3) contains in its interior an optical guide (83). Together in a beam these form the optical guide (82), located in the interior of the longitudinal keyhole (4) of the key-identifier (2).

Both the optical guides (8) and the optical guides (83) are of a diameter equal to or slightly less than the diameter of the keyholes in which they are inserted (the cross keyholes (7) and the radial keyholes (3) respectively, except in versions containing microlenses) and normally comprise one or more optical waveguides designed to conduct electromagnetic radiation from the optical spectrum, i.e. light radiation from either the visible or invisible spectrum.

The optical waveguides normally operate by means of the principle of total internal reflection, i.e. what is normally designated as optical fibers, with discontinuous and multimode refractive indices, except in the versions referred to earlier, where they may also be of the single-mode type. More economical versions may use plastic fibres.

Of the variety of processes which can be used to make the key-identifier (2), one method worth noting is moulding, where the optical guides (83) used consist only of one optical waveguide of the multi-mode type.

Thus, for example, the key-identifier (2) may be made as follows: first a star coupler is made of glass, or, if the optical guides are to be of plastic, of polystyrene or certain metacrylic resins such as metacrylate or polymethyl, where the optical coupler is made by the commonly-used mixer-rod technique. The mixer rod or cylinder constitute the optical guide (82) and receives light radiation at one of its extremities, emitting from the opposite end of the ramifications, each of which forms the core of an optical waveguide which in turn functions as an optical guide (83) and which are arranged in a size and dimensions suited to their purpose.

The aforementioned optical coupler is then inserted into a hollow piece of steel, brass or another material with the shape and dimensions required for the key-identifier, which has already been perforated with the radial keyholes (3) in the desired places. The latter is then placed in such a way that the extremity of each of its branches coincides with a radial keyhole (3).

The remaining space is then filled with a material whose refraction index is lower than that of the material of which the optical coupler is made, such as acrylic fluorinate or silicone rubber, which in addition to functioning as a filler material shall also serve as a sheath for the optical waveguides which make up the optical guides (83), and thus the key-identifier is complete.

When the key (25) is correctly inserted into the lock cylinder (24), its key-identifier (2) fits entirely into the lock-identifier (1) and the source of electromagnetic radiation (6) is activated. This source may consist of one or more LEDs, one or more small lasers or even a small light bulb. In every instance, the wavelength of the radiation emitted is suited to the type of optical waveguides used.

When the source of electromagnetic radiation (6) (located in the key (25), the optoelectronic module (12), the lock cylinder (24) or elsewhere, with the latter instance requiring an additional optical guide) is activated, the radiation emitted is focused by one or more lenses (5) onto the extremity of the optical guide (82), which, by means of the optical guides (83) which comprise it, transmits it to the interior of the key-identifier (2), from where it is propagated via the radial keyholes (3).

Here, in the radial keyholes (3) which coincide with the cross keyholes (7), the electromagnetic radiation is transmitted to the respective optical guides (8) and from here to the corresponding photodetectors (10) or the optical guides collector (9), depending on the case. Propagation does not occur when any of the radial keyholes (3) does not coincide with a cross keyhole (7).

If the key inserted is the correct one, each of the radial keyholes (3) will coincide with a cross keyhole (7), whose optical guide (8) is directly connected to a photodetector (10), while none will coincide with a cross keyhole (7) connected to the optical guide collector (9). Thus, all the photodetectors (10) except the one connected to the output of the collector will be activated. The electrical signals generated by the photodetectors will then permit the electronic circuit of the optoelectronic module (12) to determine whether the correct key has been inserted or not and the required functions shall then be activated..

If the key inserted is not the right one, not all the photodetectors (10) connected directly via the optical guides (8) to cross keyholes (7) will receive radiation, and/or the photodetector (10) connected to the output of the optical guides collector (9) shall be activated. This means that one or several of the radial keyholes (3) coincide with cross keyholes (7) connected to their inputs via optical guides, and the output of the optoelectronic module (12) shall fail to perform the desired functions.

Radial keyholes (3) and cross keyholes (7) with incorporated microlenses:

In order to reduce transmission loss between the optical guides (83) and the optical guides (8) which coincide with them - loss which is unavoidable owing to the necessary distance between their extremities - and to reduce the diameter of the optical guides used and the cables linking the lock cylinder (24) to the optoelectronic module (12) or the collectors of the optical guides (9), some versions of the present lock are fitted with microlenses in their cross keyholes (7) and the radial keyholes (3) of the key-identifier incorporated into the key (25).

These microlenses may either be conventional spherical lenses or graded-index rod lenses.

Fig. 1B shows a simplified longitudinal section of a given key-identifier equipped with the latter lens type, which is inserted into a given lock-identifier similarly equipped with the same lens. In the illustrated example, the lenses have a focal distance equal to the distance between their faces, which means that the ends of the optical guides are in direct contact with their inside faces. In this way the diverging beam of radiation at the end of each optical guide is collimated by the corresponding lens (86), which is located in the respective radial keyhole (3).

If the latter coincides with a cross keyhole (7), the beam of parallel rays will strike the lens (87), which will focus the beam on the end of the corresponding optical guide (8); thus the transfer of radiation between optical guides (83) and the corresponding optical guides (8) occurs with an enormous reduction in loss by longitudinal misalignment.

In these versions, the optical guides (8) and optical guides (83) consist of only one optical waveguide which may even be of the single mode optical fibre variety.

As fig. 1B also shows, the radial keyholes (3) and cross keyholes (7) have narrower parts (3B and 7B respectively) where the end of the optical guide is located and parts of wider diameter (3A and 7A respectively) in which the lenses are located. The diameter of these wider parts is from two to five millimetres, while the diameter of the narrower parts is equal to or slightly wider than that of the optical guide they contain.

The radial keyholes (3) and cross keyholes (7) may have small discs (90) of a transparent material such as organic glass which protect the lenses while reducing the accumulation of dust and grime.

In other versions, the interior of the lock keyhole (16) and the exterior of the key-identifier (2) may be coated with a high-durability material, such as plexiglass or lucite, which is transparent to the radiation emitted by the electromagnetic radiation source (6) but coloured to prevent the location of the radial keyholes (3) and cross keyholes (7) from being visible to the naked eye. This material would also replace the discs (90) in their protective function of the optical guide ends or the lens.

A filler material (88) may also be used in certain cases to fill the empty space in the interior of the key-identifier and to hold the optical guides in place.

The lock cylinder:

Figs. 2A, 2B and 2C show a frontal view, cross section and longitudinal section of a lock cylinder (24) for the present lock.

The lock cylinder (24) illustrated has a hexagonal keyhole (16) incorporating a retractable shutter (21) which conceals the lock cylinder when the key (25) is not inserted.

Lock keyholes (16) of any other format are also possible, though for circular keyholes the lock cylinder (24) and/or the shutter (21) will have to incorporate a mechanism which restricts the angle of rotation of the key (25) and ensures that the key-identifier always operates in the same position in relation to the lock-identifier to prevent error readings. This mechanism could for example be a nib on the key (25) which has to fit into place in a groove in the interior wall of the keyhole (16).

Small pins are located in the interior of perforations (17) and (17B) (the lock cylinder and shutter respectively) to prevent the dislocation of the shutter (21) by the action of objects other than the key (25). The shutter also incorporates a slot into which the tip (29) of the key (25) is inserted.

Thus the key is inserted in two different stages. First its tip (29) is inserted into the shutter (21) slot; if the contoured edge or indentations of various depth of the key are correct, the small pins (18) will align and allow the shutter (21) to slide back. In the second stage the key is inserted further, which forces the shutter to retract further and activate the switch or microswitch (22) which aligns the key-identifier of the key with the lock-identifier. The switch or microswitch (22) then activates the optoelectronic circuit and the key is identified.

To ensure that the key-identifier (2) is in the correct position relative to the lock-identifier (1) when the optoelectronic circuit is activated, the lock cylinders (24) in the present invention also incorporate a mechanism which holds the key firmly in place after it is inserted. In the present example this mechanism is a lever (100) in the microswitch (22) of appropriate shape and with two chamfers, (101) and (102), which clicks into place in a recess (103) in the shutter (21) when the key (25) is properly inserted. This recess has sloping extremities (104) and (105) which, together with the lever (100), permit the shutter (21) - and therefore the key (25) - to be held firmly in place. When the key is turned the shutter is then moved to the initial position for the action of the helicoidal steel spring (23).

The output of the optical guide(s) (11) leading from the lock-identifier is the keyhole (13), which in certain versions is replaced by one or two suitable contacts which permit their semi-permanent connection with the cable or cables connected to the optoelectronic module (12) or the optical guide collectors (9).

The lock cylinder illustrated has a number N_p of possible positions for the cross keyholes (7) of 7 x 6 = 42. With keys fitted with key-identifiers (2) of nine radial keyholes (3), the possible combinations are ⁴²C₉ = 4.46 x 10⁸. This means that 446 million keys can be made for this lock; the number N² of cross keyholes (7) could, for example, be eighteen. The lock cylinder also incorporates an additional pin (106) which slots into the shutter (21) recess (107), which has a sloping front edge to allow the shutter to retract and prevent its subsequent dislocation.

Description of the key:

A key suited to the lock cylinder described above is shown in figs. 3A and 3B. Fig. 3A shows a top view of the key, while fig. 3B shows a longitudinal section. As can be seen, this key also incorporates the source of electromagnetic radiation (6), and thus in addition to the key-identifier (2) and the tip (29) for opening the shutter (21) it also contains the lenses (5), a source of electrical energy (26) (e.g. a small electrical cell) for the source of electromagnetic radiation (6) and a microswitch (28) which activates the source when the key is inserted in the lock.

The optical guide collector:

The optical guide collector (9) can be fitted in a number of ways. The simplest way is obviously to collect the ends of all the optical guide (8) inputs in one bundle and locate the end of the latter in such a way that the radiation produced focuses, directly or via one or more lenses, on the photosensitive surface of a photodetector (10) which is linked to the output of the optical guide collector (9).

Alternatively, lenses can be employed to refract in parallel beams the radiation leaving each of the optical guides and to focus this collimated radiation on the tip of a single optical guide or on the photodetector (10).

A suggested optical guide collector (9) for this type is shown in simplified form in fig. 5A. This consists of a set of bi-convex lenses (62) on a suitable mounting and located at a distance from the tip of the optical guides (61), which in this case correspond to the optical guides (8), approximately equal to their focal distance. The position of each optical guide on the mounting is such that their axis is an extension of the axis of the tip of the corresponding optical guide (61). The diameter of the lenses (62) is such that the whole beam of radiation is captured. Another bi-convex lens (63), with a diameter encompassing the set of lenses (62), is located in front of the latter at a distance from the photodetector (10) approximately equal to their focal distance In this way the beam leaving each optical guide is refracted by the corresponding lens (62) into a beam of parallel rays which in turn is focused by lens (63) onto the photosensitive surface of the photodetector (10) to obtain the desired effect.

A third approach is to use a certain number of optical couplers of the combiner type, which can be employed in any of the better-known fibre optics techniques. Microlenses of variable refractory index or optical waveguide couplers are used to focus the radiation leaving the input optical guides on the output optical guide.

For example, an optical coupler/combiner with nine inputs and one output (9 x 1) can be used by means of ten lenses with variable refractory index of the parallel surfaces, i.e. a parallelepiped configuration, of a focal distance equal to the distances between their two surfaces, as fig. 4 illustrates. Each optical guide connected at one of its nine inputs is coupled to a lens (110) of the type which refracts the beam of radiation leaving the optical guide into a beam of parallel rays. These nine lenses (110) are placed parallel to each other with the opposite face in direct contact with a lens face (111), the dimensions of which allow its simultaneous contact with the whole area of the lens faces to which it is coupled and which focuses the electromagnetic radiation received by optical guide (112), which is the output of the present optical waveguide coupler.

Fig. 5B is a schematic illustration of an optical waveguide coupler with three inputs (3 x 1) - though it could have a considerably higher number of inputs - which combines in the output optical guide (57) the electromagnetic radiation transmitted by the input optical waveguides (56).

These optical waveguide couplers may be of the passive type, where the optical waveguides are positioned on a plaque (50) made of certain types of glass or other isotropic materials such as silicon dioxide or certain polymers, or active, where the plaque is made of e.g. LiNbO₃. If of the active type, the coupler will take the designation of electro-optical optical waveguide coupler or electro-optical interferometric combiner and will be fitted with a set of electrodes (54) positioned on or beside the optical waveguides, to each of which a certain potential differential is assigned in such a way as to obtain phase synchronisation between the electromagnetic waves or to modulate/demodulate the optical signal resulting from the combination of the latter. A certain number of optical waveguide couplers of one type or the other can be positioned on the same plaque (50) to form a "tree", as illustrated in fig. 5C, and to obtain an optical waveguide star coupler with the required number of inputs and only one output.

To make an optical guide collector from optical waveguide couplers a set of plaques (50) corresponding in number equal to the number of optical waveguides comprising each optical guide (8) is used. Each of the latter has a star coupler optical waveguide combiner obtained as described above and with a number of inputs equal to that required for the optical guide collector.

In each optical guide (8), each optical waveguide is connected to an input of the optical guide collector and from here to the input (52) of a different plaque (50), i.e. for each optical guide (8), one optical waveguide will be connected to one of the inputs (52) of the first plaque (50), another to an input (52) of the second plaque (50) and so on successively. The optical guide connected to the output of the collector will have each of its optical waveguides (58) connected to the output (53) of a different plaque (50), as shown in fig. 5D. In this way the radiation entering the inputs of the optical waveguide collector is transmitted to its output.

The collector is constructed in a similar way, via optical couplers/combiners with microlenses of variable refractory index. A set of microlenses is interconnected to form the necessary number of star-type optical couplers-combiners with the required number of inputs. These couplers are then connected to the optical waveguides which make up the optical guides (8) as described above.

The optoelectronic module:

As we have already seen, the optoelectronic module is an optoelectronic circuit which usually incorporates photodetectors (10) and, in certain cases, the optical guide collector(s) (9). It analyses the signals generated by the photodetectors to determine whether the key inserted is the correct one or not. If the key is the correct one, and in the existence of certain pre-established conditions, one or more functions are activated via its output, such as an electromagnetic relay which in turn activates an electric latch, or an electric lock where the present optoelectronic lock protects a certain space.

One of the pre-established conditions mentioned above might be that the limit for consecutive insertion of incorrect keys has not been reached. Another might be that after the insertion and analysis of an incorrect key, this must be withdrawn for the optoelectronic module to proceed to its next operation.

The inclusion of these two conditions - or at least the second - is extremely convenient to prevent the use of a key specially designed to exhaust the millions of possible combinations.

An optoelectronic circuit suited to the unit in question is perfectly commonplace and therefore does not require description.

Variations:

A vast number of variations to the configurations outlined above exist. Some of these are described below.

Variation A: This variation does not use any optical guide collectors (9), with each of the N2 cross keyholes (7) of the lock-identifier (1) connected by an optical guide (8) to a different photodetector (10). The optoelectronic module (12) determines whether the sequence of activated and non-activated photodetectors matches the set sequence for the lock in question. Instead of having N₁ radial keyholes (3), the key-identifier (2) has a number of cross keyholes which varies between one and N₂, depending on the number of photodetectors to be activated.
Variation B: Here, when the correct key (25) is inserted the photodetector (10) connected to the output of the optical guide collector (9) is not activated, while the set of photodetectors (10) (activated and non-activated) connected via optical guides (8) to the lock-identifier (1) ) form a pre-defined sequence.

Variation C: In this variation the source of electromagnetic radiation (6) is located in the key (25) and emits a modulated radiation, which can vary from key to key - and among different keys for the same lock - and allows the lock to recognise and differentiate between the different keys which can activate it and the different functions to be activated. For this purpose its optoelectronic module (12) is fitted with a special electronic circuit.

The modulation required for this variation can be obtained either via the modulation of the electronic signal which feeds the source of electromagnetic radiation (6) or via the use of an optical or electro-optical modulator located (usually) in the key between the source of electromagnetic radiation (6) and the lenses (5).

Variation D: The use of optical guides in the present lock makes it possible to dispense with the keyhole (16). This may be a major advantage, since it is often the keyhole which is the most vulnerable part of a lock.

Figs. 6A and 6B show the longitudinal section of a suggested lock cylinder (24) of this variation and a longitudinal section of the corresponding key 25. As can be seen, their shape is reminiscent of a connector.

When the key is inserted or fitted into the lock cylinder (24), the contact surface of the key-identifier (2) and the lock-identifier (1) is flat, i.e. contact occurs entirely on the same plane.

Both the lock-identifier (1) and key-identifier (2) of this variation have a set of perforations - (96) and (97) respectively - which are perpendicular to the plane of contact and correspond to cross keyholes (7) and radial keyholes (3) of the versions of the present optoelectronic lock which include a keyhole (16). In a similar way to the other versions, perforations (96) and (97) each contain one tip of an optical guide (8), part of optical guide (83) and sometimes - as in the example illustrated - lenses (87) and (86).

In the present example, the source of electromagnetic radiation (6) is located in the optoelectronic module (12), with the radiation transmitted to the lock cylinder (24) by the optical guide (73). When the key (25) is inserted or fitted, the radiation is transmitted by the lens of variable refractory index (91) to the star-type optical coupler (92) and is then divided among the optical guides (83) connected to the outputs of the star coupler. These transmit the signal to the lenses (86) (in the case, of variable refractory index), from where it is transferred to the matching lenses (87) and from there to the matching optical guides (8).

The star-type optical coupler (92) reduces radiation loss in its transmission from the lens (91) to the optical guides (83). It can also be used in a similar fashion in versions with keyholes (16) to transmit light signals from the source of electromagnetic radiation (6) and/or lenses (5) to the optical guides (83).

In this variation, both the lock cylinder (24) and the key (25) incorporate a plaque (71 and 81 respectively) made of a high-durability material, such as plexiglass, lucite, or even sapphire, which is transparent to the radiation emitted by the electromagnetic source (6) but coloured in such a way as to prevent the tips of the optical guides (8) and (83) - or the lenses (86) and (87), depending on the case - from being seen. They also offer physical protection for the lock-identifier (1) and key-identifier (2).

The key (25) has two nibs (93) which fit into corresponding grooves (94) in the lock cylinder (24) to ensure that the key is inserted properly.

The remaining space in the interior of the casings (76 and 80, respectively) of the lock cylinder and key can be filled with any filler material. Figs. 7A and 7B show frontal views of the lock cylinder and key respectively.

The lock cylinder (24) used in any versions and/or variants may also contain a physical integrity testing system consisting of a transmission segment or track which spans the interior of the lock cylinder and breaks if the lock cylinder is subject to abusive or violent attempts at access. This segment or track is connected electrically to the optoelectronic module (12). Its breakage informs the optoelectronic module of the attempts to gain illegitimate access and the lock becomes blocked for an indeterminate period.

Finally, it should be noted that throughout the present document the terms "activated photodetector" and "activated optoelectronic device" are used for those receiving luminous radiation on their photosensitive surfaces. In the absence of such radiation they are considered inactive or non-activated.

In versions of the present optoelectronic lock fitted with a keyhole (16) and where the key-identifier (2) for the corresponding key(s) is made by processes not confined to moulding, to facilitate the insertion of the optical guides (83) and/or optical coupler (92) and/or lenses (86) the key-identifier may be made in two separate halves corresponding to the longitudinal section thereof The necessary components can then be placed in the interior of the halves (e.g. optical guides (83) before they are joined together and covered, if desired, by an external casing of the required shape and dimensions to make the key-identifier (2).

Where microlenses are used in the lock-identifiers (1) and key-identifiers (2), these may be located only at the tip of the corresponding optical guide, i.e. when manufacturing the optical guide the microlens could be fitted to the tip at the same time.

Where any of the optical guides used in the present lock comprise more than one optical waveguide, each one is formed by bringing together the waveguides in a bundle or any other arrangement and covering them in an external wrapping of any type or material. The tips of the optical guides located in cross keyholes (7), radial keyhole (3) or perforations (96) or (97) may contain a star coupler implemented by the mixing rod process, of which the input optical waveguides constitute the optical guides in question. The output of the optical guides is the opposite tip, while the mixing rod of the coupler is located in the interior of the corresponding keyhole or perforation.

Claims

Optoelectronic lock for protecting access to areas, vehicles or machinery and incorporating:

device for optical recognition of the key(s);

optical transmission/propagation of electromagnetic radiation;

optical or electro-optical device for combining in a single output, in electrical or optical signals, the electromagnetic radiation proceeding from the various inputs;

optoelectronic system in a remote location from the referred to devices for optical recognition of the key(s) which translate or convert optical signals into electrical signals;

electrical and/or electronic means located remotely from the referred to devices for optical recognition of the key(s) by analysing the electrical signals generated by the aforementioned remote optoelectronic device and activating one or more functions when the key inserted is correct and certain conditions exist;

electrical, optoelectronic or other means for the generation and emission of electromagnetic radiation belonging to the optical spectrum of the latter; and

one or more keys, each equipped with optical, electro-optical or other means for defining the respective code in conjunction with the aforementioned optical recognition system.
Optoelectronic lock as described in specification 1, characterised by the aforementioned means of optical recognition of the key being equipped with a number of perforations in each of which is located the tip of one of the aforementioned optical devices for transmission/propagation of electromagnetic radiation. These perforations may also each include one or more lenses (87) of any type, and/or a disc (90) of a material transparent to the radiation emitted by the aforementioned means of generation and emission of electromagnetic radiation; in the versions of the present lock where there exists a keyhole (16) into which the key or keys (25) are introduced, this is incorporated into the system for optical recognition of the key(s), can be of any profile and format and intercepts the aforementioned perforations.
Optoelectronic lock as described in specifications 1 and 2, characterised by each of the optical devices for transmission/propagation of electromagnetic radiation generally consisting of one or more optical guides located together on a bundle or in any other arrangement and enclosed inside an external casing of any type or material; the aforementioned optical guides may be of any type, e.g. optical guides operating on the principle of total internal reflection; the optical guides for transmission/propagation of electromagnetic radiation have, where one of their extremities is inserted into one of the aforementioned perforations, a diameter identical to the diameter of the perforation, except where the perforation contains one or more lenses (87).
Optoelectronic lock as described in specification 1, characterised by the aforementioned optical or electro-optical device, which combines in a single output the electromagnetic radiation proceeding from the various inputs, being implemented in a variety of different ways, viz.:

by combining in a bundle the aforementioned optical device for transmission/propagation of electromagnetic radiation, connected to the inputs and positioned in such a way that the radiation proceeding therefrom strikes, directly or indirectly after being focused by one or more lenses, the photosensitive surface of one of the aforementioned remote optoelectronic devices;

via one or more lenses of varying types to focus the electromagnetic radiation proceeding from any of the inputs on one of the aforementioned optical devices for transmission/propagation or one of the aforementioned remote optoelectronic devices;

employing optical couplers/combiners which can be implemented by a variety of processes and which are interconnected in such a way as to constitute the necessary number of star-type optical couplers/combiners, each of which has the necessary number of inputs and only one output.
Optoelectronic lock as described in specification 1, characterised by the aforementioned optoelectronic devices positioned at a location remote from the aforementioned devices for optical recognition of the key(s) generating electrical signals from the electromagnetic radiation they receive, and also characterised by the fact that in most cases they are suited/adapted for the reception of this radiation proceeding from the aforementioned optical devices for transmission/propagation of electromagnetic radiation and furthermore by being normally positioned next to the aforementioned remote electrical or electronic devices.
Optoelectronic lock as described in specification 1, characterised by the aforementioned remote electrical or electronic devices sometimes incorporating:

the aforementioned electrical, optoelectronic or other means for the generation and emission of electromagnetic radiation, and/or

a device for testing whether the modulation frequency of the radiation emitted by the aforementioned means for generation and emission of electromagnetic radiation is correct, where the latter emit modulated radiation, and/or

means for deactivating the lock for a certain period of time when the physical integrity testing device with which the lock may be equipped indicates that the lock is or has been subject to abusive and/or violent attempts to open and/or unblock it.
Optoelectronic lock as described in specifications 1 and 6, characterised by the aforementioned electrical, optoelectronic or other device for the generation and emission of electromagnetic radiation being of various types, incorporating means for the transmission and coupling the radiation transmitted to the aforementioned optical device for the transmission/propagation of electromagnetic radiation and further characterised by:

the optional inclusion of one or more light-emitting diodes, one or more small lasers or a small light bulb of any type;

the possibility of being located in the aforementioned key(s) (25), or next to the aforementioned device for the optical recognition of the key(s), or in the aforementioned remote electrical/electronic device, or at any other location; in the latter two cases the radiation emitted is transmitted to the aforementioned device for optical recognition of the key via one of the aforementioned optical devices for the transmission/propagation of electromagnetic radiation;

the optional incorporation of electrical, optical or electro-optical means for modulating the radiation received.
Optoelectronic lock as described in specification 2, characterised by the aforementioned means for optical recognition of the key being incorporated into the lock cylinder (24), normally located in the area or object to be protected, and incorporating:

a device for ensuring that the optical recognition of the aforementioned key (25) is performed by the aforementioned optical, electro-optical or other device of the latter in the correct position relative to the aforementioned device for optical recognition of the key,

means to enable output of the aforementioned optical device in the lock cylinder to transmit/propagate electromagnetic radiation and/or allowing the coupling and connection of the optical devices located in the interior of the lock cylinder with those outside, and

where the lock is equipped with the aforementioned keyhole (16), optional means in some cases for concealing the latter in the absence of the aforementioned key (25) and simultaneously preventing the introduction of other objects in the keyhole; such a device also activates a switch or microswitch (22) after the insertion of the key in the lock which in turn activates the aforementioned remote optoelectronic, electrical or electronic device and, in some cases, the aforementioned means for generation of electromagnetic radiation.
Optoelectronic lock as described in specifications 1 and 7, characterised by the aforementioned key(s) in some cases incorporating, in addition to the respective optical, electro-optical or other device, the aforementioned electrical, optoelectronic or other device for the generation and emission of electromagnetic radiation, in which case the key(s) also contain(s) a switch or microswitch (28) which activates the latter when the respective key is inserted into the lock, plus a source of energy (26), e.g. a small electrical cell.
Optoelectronic lock as described in specifications 1 and 9, characterised by the aforementioned optical, electro-optical or other device with which the key(s) is/are equipped having:

format and dimensions permitting insertion into and/or adaptation to the aforementioned device for optical recognition of the key(s); and

A number of perforations which each contain part of the aforementioned optical means of transmission/propagation of electromagnetic radiation, and in some cases one or more lenses (86) of any type, or a star-type optical coupler, and/or one of the aforementioned discs (90) of a transparent material, and further characterised by the aforementioned perforations being in such a position that they all coincide, when the respective key is correctly inserted/adapted/placed in the lock for which it was built, with some of the perforations of the aforementioned optical recognition device of the key.
Optoelectronic lock as described in specification 10, characterised by being fitted with an optical device which conducts, transmits and couples the radiation emitted by the aforementioned electrical, optoelectronic or other device for the generation and emission of electromagnetic radiation to the aforementioned optical device for the transmission/propagation of electromagnetic radiation, part of which is located inside the perforations of the aforementioned optical, optoelectronic or other device of the key(s), with the radiation emitted thus emanating from the aforementioned perforations.
Optoelectronic lock as described in specification 2, characterised by each of the perforations of the aforementioned device for optical recognition of the key which have to coincide with one of the perforations of the aforementioned optical, optoelectronic or other device of the key(s) (25) for the respective lock being connected directly and individually, via one of the aforementioned optical devices for transmission/propagation of electromagnetic radiation, to one of the aforementioned remote optoelectronic devices, with each of the remaining perforations of the aforementioned device for optical recognition of the key also connected, also via one optical guide the aforementioned optical devices for transmission/propagation of electromagnetic radiation, to one of the inputs of the aforementioned optical or electro-optical devices for combining in a single output the electromagnetic radiation proceeding from the inputs; the output of the latter, when in optical format, will be connected to one of the aforementioned remote optoelectronic devices.
Optoelectronic lock as described in specifications 1 and 6, characterised by the optional incorporation of a physical integrity testing device consisting, for example, of a transmission segment or track located in the lock cylinder (24) and electrically connected to the aforementioned remote electrical and/or electronic device, which inform the latter, for instance by breaking of the circuit, of abusive and/or violent attempts at activating/forcing the lock.
Optoelectronic lock as described in specifications 2 and 10, characterised by the perforations of the aforementioned optical recognition of the key having a diameter equal to or slightly greater than the diameter of the aforementioned optical, electro-optical or other device of the key(s) (this diameter is normally around two to five millimetres), and with the latter perforations optionally incorporating, instead of one or more lenses (87), a star-type optical coupler.
Optoelectronic lock as described in all the above specifications, characterised by the possible absence of a keyhole (16) in which the key (25) or part thereof is inserted; thus the contact surface between the aforementioned device for optical recognition of the key(s) and the aforementioned optical, electro-optical or other device of the key is, in most cases, limited to a plane surface via which the optical recognition of the key(s) is effected.
Optoelectronic lock as described in specifications 2, 10 and 11, characterised by the fact that both the aforementioned device for optical recognition of the key and the aforementioned optical, electro-optical or other device of the key may, instead of the aforementioned discs (90) of transparent material, be covered with a high-durability coating or plaque (71 and 81) which:

is transparent to the radiation emitted by the aforementioned electrical, optoelectronic or other device for the generation and emission of electromagnetic radiation, and:

at the same time, prevents the location of the perforations of the aforementioned device for optical recognition of the key(s) or aforementioned optical, electro-optical or other device of the key(s) from being visible to the naked eye, and also:

is located in the aforementioned device in the part which contacts with other parts thereof and/or via which optical coupling takes place.
Optoelectronic lock as described in all the above specifications, characterised by the fact that all the aforementioned remote optoelectronic devices are activated, with the exception of that which is incorporated into or connected to the output of the aforementioned optical or electro-optical device for combining in a single output the radiation proceeding from the inputs, when the correct key (25) for the lock in question is properly inserted/adapted/connected (in)to the latter; the active remote optoelectronic device here signifies that which receives electromagnetic radiation via the aforementioned optical device for the transmission/propagation of electromagnetic radiation to which it is connected.
Optoelectronic lock as described in specifications 1, 4 and/or 12, characterised by the fact that the aforementioned optical or electro-optical device for combining in a single output the electromagnetic radiation proceeding from the inputs is normally located remotely relative to the aforementioned device for optical recognition of the key(s).