WO1994020335A1

WO1994020335A1 - Security system for a motor vehicle

Info

Publication number: WO1994020335A1
Application number: PCT/GB1994/000433
Authority: WO
Inventors: Brendan Gerard Duckworth
Original assignee: Brendan Gerard Duckworth
Priority date: 1993-03-05
Filing date: 1994-03-07
Publication date: 1994-09-15
Also published as: AU6147894A

Abstract

Means (26) for use on or in a vehicle are adapted to provide a programmed or programmable display (38) for security use and/or for display to persons outside the vehicle and may comprise a vehicle windscreen, window or registration number plate (28), part or all of which is programmable to be substantially transparent and alternatively at least partially opaque and/or may comprise a vehicle registration number plate (28) with a programmed or programmable display (38), e.g. provided by appropriate display means (34), e.g. liquid crystal, e.g. with a lambertian light source (36) arranged to provide back illumination therefor. The programmable or programmed display (38) may be characteristic of the vehicle being stolen or otherwise in an unauthorised state, e.g. by being opaque or exhibiting the word 'STOLEN' (38) and/or it may show the vehicle registration number (381), e.g. alternately. It may respond to an authorisation signal (48), e.g. coded, to prevent or suppress exhibition of the unauthorised state display (38), or respond to a vehicle ignition detection signal (50) and the absence of an authorisation signal (48) to enable exhibition of the unauthorised state display (38), or enable exhibition of the unauthorised state display (38) only above a predetermined threshold speed of the vehicle.

Description

SECURITY SYSTEM FOR A MOTOR VEHICLE BACKGROUND

This invention relates to vehicle security systems and means particularly for use in such systems but possibly having other applications.

The whole of the present inventor's prior British patent specification GB9304562 is hereby imported into the present specification.

Many vehicle security systems are currently available, which are generally based

on audible alarms and/or vehicle immobilisation. However, it frequently happens that

thieves manage to circumvent such systems and drive the vehicle away. THE INVENTION

The present inventor has appreciated that the main disadvantage of such prior systems, when the thief manages to circumvent the system and drive the vehicle away, is that it is then not apparent to the public or the relevant public whether the vehicle has been stolen or is being used by an authorised driver. According to one aspect of

the invention, there is provided a vehicle security system, characterised in that it is adapted to give a visible alarm or other externally visible indication characteristic of the vehicle being stolen or otherwise in an unauthorised state. Preferably, the indication is not visible or readily apparent to the thief, especially when stealing (e.g. entering) and/or driving the vehicle. However, some of the features or combinations of features developed by the inventor for this purpose, and described herein, can have other applications. The principle can be extended to other unauthorised use than theft, for example exceeding a speed limit for the vehicle (or a speed limit for the area in which the vehicle is travelling, e.g. if the vehicle has means to detect or receive information indicating such a speed limit as it passes through the area), and/or driving the vehicle with a load exceeding an authorised limit, with seat belts not fastened,

and/or with a fitted tachograph disconnected.

According to another aspect of the invention there is provided a vehicle security system as claimed in claim 9. The features of claim 10 allow embodiments that are particularly versatile and economical to produce. The features of claim 11 allow embodiments that are particularly economical and convenient for use. The vehicle registration number plate can be used in such a vehicle security system or may be used in other applications, for example simply as a vehicle registration number plate that is very versatile and can be pre-manufactured to be programmable and then rapidly programmed to display a particular vehicle registration number. According to another aspect of the invention there is provided a vehicle registration number plate as claimed in claim 4. The term "vehicle registration number" refers to any index that indicates the registration of a vehicle, whether it is composed solely of figures or a combination of figures and letters or otherwise. The term "programmable" refers to the ability of the display means to display different information according to its programming. In a very simple case, one display could be the vehicle registration number and another display could be a blanking out of the same but a very much more useful programming would be one in which one display is a vehicle registration number and another display is a different intelligent message. The term "programming" can have reference to the selection of elements of a display so as to provide a particular intelligent message, e.g. a vehicle registration number, and/or the ability to switch from one display to another.

The system of claim 9 may not be sold complete but appropriate elements of it

may be sold for fitting into a custom-made security system and according to further aspects of the invention there are provided means as claimed in claim 7 and means as claimed in claim 8.

The system of claim 9 may be arranged to provide a display that simply flashes

on and off, however a much more useful system is one having the features of claim

12. While the display may be characteristic of unauthorised use (e.g. an opaque area of the vehicle's windscreen), it is much more useful if the display indicates (to others)

that the vehicle is stolen or otherwise in an unauthorised state, as claimed in claim 13.

The indication may be visible to the public at large or it may be discernible only to

a relevant public, e.g. the police, e.g. having special receiving or detecting equipment, e.g. a polariser, e.g. incorporated in the windscreen of a police vehicle and used in conjunction with a polarisation of the display to indicate that the vehicle is in an unauthorised state.

While the indication may be a suppression of the vehicle registration number, a much more useful indication would be provided by a system as claimed in claim 14, because this would enable ready identification of the vehicle being used in an unauthorised state. A particularly economical and striking display means would have the features of claim 15, e.g. with the displays alternating at intervals of half to three seconds, preferably half to one second.

A useful display may be obtained having the features of claim 16, since this could be for example readily remarked by the police (being, in the case of a system as claimed in claim 17, very similar to a feature which they are accustomed to noticing, i.e. when the vehicle registration number has a substantial area obscured, or being, in

the case of a system as claimed in claim 18, something else which they readily notice, i.e. an unsafe obscuration on a vehicle windscreen). In the case of the features of

claim 18, driving of the vehicle may be rendered very difficult or impossible.

Particularly in the case of the alternating displays of a system as claimed in claim

15, but also in other cases, a system having the features of claim 19 will be readily

noticeable by the public at large and, in the case of a system as claimed in claim 15, the public will be able to recognise readily, quickly and easily that the vehicle is in an unauthorised state and is stolen and be able to report the matter rapidly to the police or (depending upon local law and circumstances) be able to take action themselves. The display may comprise the word "stolen", the equivalent in another language than English and/or a symbol (perhaps internationally recognised) indicating theft.

The display control means may, as appropriate, serve to drive the display means, programme the display means and/or switch the display means from one display state to another. The display means may comprise a vehicle registration number plate and/or an obscurable section of the vehicle's windscreen, and these may be individually and appropriately controlled by the display control means.

The display control means may be adapted to respond in various ways in order to control the display means. For example, the display control means may allow permanent exhibition of the unauthorised state display when the vehicle is not in use, or at rest (subject to local law). For some purposes, it is particularly useful to

provide a system with the features of claim 20, for example the response to the authorisation signal causing the display control means to bypass any part of itself that has the function to enable exhibition of the unauthorised state display. For other purposes, it may be more appropriate and useful, e.g. in a fail-safe embodiment, for an enabling signal for exhibition of the unauthorised state display to be produced but for this to be suppressed in response to an authorisation signal, in a system as claimed in claim 21. Although there may be other signals (e.g. one indicative that the vehicle is moving, e.g. connected to a speedometer of the vehicle), a particularly useful and

readily installable embodiment is one having the features of claim 22. The vehicle ignition detection signal may, for example, be generated by an inductive loop which is located and arranged for detection of the surge of what is usually a relatively very

large ignition current. This has the particular advantage that the loop need not be

close to the conductor carrying the ignition current and therefore may be difficult for a vehicle thief to locate, distinguish and/or disable. Use of a vehicle ignition detection signal is not limited to a system as claimed in claim 22. Also, the system may be adapted to respond to some other signal indicative of the vehicle being stolen together with the absence of an authorisation signal to enable exhibition of the unauthorised state display.

A system as claimed in claim 23 has the advantage that the thief may not normally be able to detect the unauthorised state display when the vehicle is travelling slowly, e.g. up to 5 mph (or 10 kph) or up to 10 mph (or 20 kph).

The security control means may have the features claimed in claim 24, a security

switch being for example a switch which is normally hidden or again one which requires a key (separate from the ignition key) to operate it. Again, the security switch might be combined with the ignition switch and require a particular combination of movements and perhaps timing of the ignition key to produce the authorisation signal. For example, it may be set to require the key to be turned from the previous position to the normal running position and back again three times in six seconds to generate the authorisation signal and to generate an "unauthorised state"

control signal if switched less than this number of times or more than this number of

times in the specified period. Such an "unauthorised state" signal would then be arranged to overridingly cause exhibition of the unauthorised state display (either immediately or, for example, upon the vehicle reaching a predetermined threshold speed). An alternative security control means may have the features claimed in claim

25, this having the advantage that the keyboard need not be hidden (and might then indicate to a potential thief that there is a special security system in operation and thus deter theft) and possibly having the advantage that the authorised driver can use the familiar idea of a PIN number.

Any of the above-mentioned signals may be coded and it is particularly helpful to the degree of security to provide a system having the features claimed in claim 25.

At this point, reference is made to the passage in specification GB9304562 from the beginning of the paragraph starting at line 14 on page 1 to line 1 on page 3, quoted as follows:

"According to a first aspect of the present invention there is provided a vehicle security system comprising an LCD for fixing to a visible part of the vehicle, electronic drive circuitry adapted so as to accept an authorised use signal and to send a signal to said LCD whereby the visual appearance of the LCD is altered from a first state to a second state as a result of said authorised use signal, the system being

arranged so that in the absence of said authorised use signal the LCD remains in the aforesaid first state.

"Preferably, the LCD takes the form of a liquid crystal film bonded firmly to the entire visible surface of the vehicle's number plates. When fitted in this manner, the film assumes its first state which is opaque when there is no voltage applied to it, this corresponding to the condition of no authorised use signal. Once the authorised

use signal is sent to the drive circuitry, a voltage is applied to the film which causes it to transform to its second, transparent state.

"Thus, unless the vehicle is being used by an authorised driver, the vehicle's number plates will be unreadable and the vehicle will thus be visibly marked as stolen.

"The film is preferably manufactured using a polymer displaced lead crystal.

"The authorised use signal may be derived from a simple hidden switch or

from a more sophisticated security system offering vehicle immobilisation and visual and audio alarms, the latter arrangement using means such as an infra-red remote control to "arm" the system when parking the vehicle. When combined with an existing security system, the system of the present invention gives an added

enhancement, although significant protection is given even when the system of the present invention is used alone. "Whilst it is anticipated that the liquid crystal film would be bonded to the number plates, it could equally be bonded to other parts of the vehicle, for example part or all of the windscreen and/or windows.

"The system may be incorporated into the vehicle during manufacture, or may be retro-fitted to existing vehicles. " According to a second aspect of the present invention there is provided a vehicle fitted with a security system comprising an LCD fixed to a visible part of the vehicle, electronic drive circuitry adapted so as to accept an authorised use signal and to send a signal to said LCD whereby the visual appearance of the LCD is altered

from a first state to a second state as a result of said authorised use signal, the system being arranged so that in the absence of said authorised use signal the LCD remains

in the aforesaid first state.

"The system is inherently tamper-proof, in that a voltage is necessary to render

the film transparent, so that if the electrical connection to the film is cut, no voltage

can be applied and the film remains opaque."

Reference will now be made by way of example to the accompanying drawings, in which:-

Figure 1 is a version of the sole Figure of specification GB9304562 but without the legends; Figure 2 is a schematic representation of other embodiments of the invention;

Figure 3 is a schematic front elevation of a vehicle embodying the invention; and

Figure 4 is a schematic detailed block diagram of part of a display control means for use in embodiments of the invention.

Reference is now made to the drawings. In the various embodiments, references having the same first pair of digits denote similar members.

Referring now more particularly to Figure 1, reference is here made to the passage in specification GB9304562 from the beginning of the paragraph starting at line 6 on page 3 to the end of the description, quoted after the present paragraph, subject to it being understood that this refers only to one embodiment of the present invention. In Figure 1, the boxes 12 represent the front number plate display and the boxes 14 the rear number plate display, box A in each case representing the display with the signal absent so that it cannot be read, and the box B representing the display with the signal present so that the display can be read normally. Box 16 represents the core electronics, signal 18 is the "authorised use" signal. When this signal is asserted (present), the number plates can be read normally. Box 20 represents the remainder of the vehicle security system. The major function of this block is to provide the

"authorised use" signal. This block may also provide other conventional vehicle security features. It is possible to combine the core electronics 16 with this block 20.

Entering block 20, there is shown vehicle power supply 22. There is shown as an output from core electronics 16 a signal voltage 24 going to the front and rear number

plates 12, 14, although in some embodiments it is preferable that the security system

should only affect the rear number plate. Voltage 24 is a "clear number plate" signal.

When it is present, the plates are clear to enable the number display to be read normally. When it is absent, the plates are opaque to reading the number display.

The term "opaque" is used to mean that the transparency is substantially reduced so as to make it very difficult or impossible to read the display through the opaque area.

"Referring to the drawing, the system of the present invention is designated generally by reference numeral 10 and comprises an LCD in the form of a liquid crystal film manufactured from polymer displaced lead crystal permanently bonded to the entire visible surface of one or both front and rear number plates 12,14 of a vehicle. Two light gauge wires connect the film bonded to each plate to electronic

circuitry 16. By applying a suitable voltage to the liquid crystal film it can be

changed from a first, opaque state A to a second, transparent state B. When the film is opaque, the contrast of the underlying number plate is greatly reduced making it difficult to read, whereas when the film is transparent the number plate can be read normally.

"When the vehicle is being driven by the rightful owner, the security system is disarmed by the owner initiating an authorised use signal 18, from the remainder 20 of the security system, whereby a voltage 24 is applied to the film on each number

plate to render the film transparent.

"Both the electronic circuitry 16 and the remainder 20 of the security system are powered from the vehicle's own power supply 22. If an unauthorised user succeeds in breaking in to the vehicle and driving it away, the circuitry does not receive an authorised use signal, no voltage is applied to the film which therefore

turns opaque so that the number plates are unreadable. This clearly marks the car as having been stolen to passers-by as well as to the police.

"The electronic circuitry notionally comprises two parts. The "core" electronics 16 provides the energising voltage 24 for the liquid crystal film on the number plates. This circuitry accepts an authorised use signal from the remainder of the security system 20 which can be as simple or complex as required. In its simplest case this can be a hidden switch, but it may comprise a more sophisticated, conventional vehicle security system. It is possible to combine the core electronics 16 with the remainder 20 of the security system.

"The primary function of the core electronic circuitry is to provide a voltage which changes the transmission ratio of the liquid crystal film. The circuitry will be capable of providing sufficient voltage and current to drive two LCD films of size large enough to cover any of the standard number plate formats, from their opaque to transparent states. The voltage required to change the LCD films to their transparent state increases markedly as the temperature of the film decreases. The output waveform and frequency is chosen to minimise potential interference to neighbouring electrical systems. The core electronic circuitry will be capable of operating over a normal vehicle DC supply range. Current consumption will be minimised. The core electronic circuitry will be fully protected against an accidental short circuit on the output LCD drive connections. Normal electrical disturbances on a vehicle supply

will not affect the operation of the circuitry.

"The core electronic circuitry will be housed in an enclosure suitable for

mounting on a vehicle. This enclosure will prevent damage to the electronic components by penetration of moisture or liquids. The circuitry will be capable of

normal operation in a typical vehicle "under-bonnet" environment."

References herein to two displays being exhibited alternately include the

possibility that one lasts longer than the other, the possibility that both of them flash alternately and/or the possibility that one or both displays flashes up for a short period followed by a short period of no display before the other one appears. References to a liquid crystal display (LCD) means may, as the case will admit, embrace reference to other types of display means, for example those used for digital electronic calculator or clock displays and/or thermochromic and/or electrochromic display means. The security control means may be actuable by an "intelligent card". The display means may comprise a programming or driving means having a control box which can be used by a retailer of a programmable vehicle registration number plate to set the normal display of the vehicle registration number, for example by means of dip switches or insertion or connection of resistors, the whole control box then being filled with suitable resin to form a sealed unit, which may further be made impervious

to X-ray investigation and/or analysis by means of internal shielding, so that the control box can only be opened destructively, with a view to avoiding or making extremely difficult or time-consuming the possibility of changing the number on the number plate. The control box can also be bonded to the number plate so that it cannot be separated therefrom and replaced except in a manner destroying the number

plate or at least a display portion thereof. It is assumed that any person having the

security system fitted will not want the control box to be left unsealed and able to be changed. Indeed, if such a system is found, e.g. by the police, this could be taken as evidence of intended use of the number plate for nefarious purposes. A lambertian light source is one which will provide background illumination to the same degree in all relevant directions, preferably substantially uniform throughout the area of the display of the number plate. The number plate may be operated, for example, by a sequential signal at 33khz for normal display, in known manner. Alternatively, parallel operation of the relevant segments of e.g. an LCD may be provided with a reasonably small number of wires, e.g. ten wires, of which seven go the respective segments of a standard numeral and three are combined binarily to select one of seven digit positions in the display, a small number of extra wires being used if letters are to be displayed in addition to figures. Referring now more particularly to Figure 2, a vehicle security system 26 comprises a vehicle registration number plate display means 28 that is programmable or programmed, display control means 30 adapted to control the display means 28 and security control means 32 for the display control means 30. The display means 28 comprises a liquid crystal vehicle registration number display means 34 with a lambertian light source 36 arranged to provide back illumination for the display means

34. The display means 34 is adapted to exhibit a display 38 that is characteristic of the vehicle being stolen and indicating to the public at large that the vehicle is stolen. The display means 34, as illustrated for clarity as separate display means 341 but in fact being the same display means 34, is adapted to exhibit a vehicle registration number display 381 in addition to the unauthorised state display 38, and moreover to exhibit the two displays 38 and 381 alternately. In an alternative embodiment, see

Figure 1, the unauthorised state display 12A comprises a substantial area 382 of opacity, as described above. In a further embodiment shown in Figure 3, said area of

opacity comprises a substantial area 383 of the windscreen 40 of the vehicle 42, preferably said area 383 blocking the forward vision of the driver 44.

The display control means 30 comprises means 46 adapted to respond to an

authorisation signal 48 to prevent or suppress exhibition of the unauthorised state

display 38. In particular, means 46 is adapted to respond to a vehicle ignition detection signal 50 and the absence of an authorisation signal 48 to enable exhibition of the unauthorised state display 38. This is achieved by passing signals 48 and 50 to respective flip-flops 52, 54, each of which is switched over upon receiving the

respective signal 48 or 50 and gives a continuous output 56, 58 thereafter. Signal 56 is fed through a NOT gate 60 and the resulting signal 62 together with signal 58 is passed to an AND gate 64 which gives an output 66 if both of the input signals are present. A delay circuit 68, e.g. comprising essentially a capacitor, delays signal 66

for a predetermined time (to allow the driver to produce the authorisation signal after the vehicle ignition detection signal). If this time is exceeded without signal 48 appearing, which would reduce signal 66 to 0 and hence switch off the delay device 68, the delay device 68 produces an output signal 70 which enables display 38. In a

further embodiment, there may be provided a second AND gate 72 which has as one input the signal 70 and as a second input a signal 74 indicative of the vehicle having reached a predetermined threshold speed. In this embodiment, an output signal 76 is only produced if the vehicle 42 is in an unauthorised state (e.g. stolen) and has reached the threshold speed, in which case signal 76 can then enable display 38.

Security control means 32 may comprise a security switch 80 adapted to respond to operation thereof to transmit authorisation signal 48 to the display control means 30 or may comprise a touch pad or other keyboard 82 adapted for the input thereto

(usually by the driver) of an authorisation code and in response thereto to transmit the

authorisation signal 48 to the display control means 30. Preferably, security control means 32 comprises an encoder 84 adapted to produce the authorisation signal 48 in a coded form and means 46 comprises a corresponding decoder 85, for the reasons given above. Display control means 30 may comprise a display control unit 86 adapted to present the displays 38 and 381 alternately on the same LCD display means 34 and may additionally and at the same time produce the opaquing of area 383 in a "safe" (for the vehicle owner, to stop the vehicle being driven away) or "fail-safe" (for the driver) manner, as desired, i.e. with opacity or transparency respectively upon zero (failure of) voltage, though perhaps depending upon local laws. For safety, it is preferable to arrange that the opaquing of area 383 occurs gradually and/or in stages so that a thief driving the vehicle does not have his view suddenly cut off in the embodiment in which the opaquing occurs only above a threshold speed.

Although reference has been made to an LCD display means, other forms of display means are known and/or being developed. The unauthorised state indication may be a change in the colour or colours of the display. Again, because of the use of programming, the unauthorised state indication may be quite subtle or unobvious to most members of the public, e.g. a change in the shape or spacing of the index characters of the registration number or their order into an unusual or non-standard form. For example, in a country in which a set of figures normally follows a set of letters, the order of the two sets can be interchanged, which would be obvious to the

police but unobvious to other members of the public, yet still readily denoting the

identity of the vehicle. The registration number plate may have a front panel, part or all of which is programmable to be substantially transparent and alternatively at least partially opaque.

It will be apparent to those skilled in the art that features of the different

embodiments disclosed herein and by importation from prior specification GB9304562

may be omitted, selected, combined or exchanged and the invention is considered to extend to any new and inventive combination thus formed, in its own right.

According to further aspects of the invention there are provided a vehicle registration number plate, display means, a vehicle security system, vehicle security

means and/or a vehicle as claimed in any one or more of claims 1 to 3, alone or in any combination with each other or with any of the other claims.

Claims

1. Means for use on or in a vehicle, characterised in that said means are adapted

to provide a programmed or programmable display for security use and/or for display to persons outside the vehicle.

2. Means as claimed in claim 1, characterised in that said means comprises a vehicle windscreen, window or registration number plate, part or all of which is programmable to be substantially transparent and alternatively at least partially opaque.

3. Means as claimed in claim 1 or 2, characterised in that said means comprise

a vehicle registration number plate with a programmed or programmable display.

4. For use in a vehicle security system or otherwise, a vehicle registration number plate, characterised in that it comprises a display means that is programmable or programmed.

5. A number plate as claimed in claim 4, characterised in that it comprises a liquid crystal vehicle registration number display means.

6. A number plate as claimed in claim 4 or 5, characterised in that it comprises a lambertian light source arranged to provide back illumination for the display means.

7. Vehicle security means, characterised in that it comprises a vehicle registration number plate that comprises a display means that is programmable.

8. Vehicle security means, characterised in that it comprises a vehicle registration number plate that comprises a display means that is programmable and display control means for the display means.

9. A vehicle security system, characterised in that it comprises a vehicle registration number plate or like display means that is programmable or programmed, display control means adapted to control the display means and security control means for the display control means.

10. A system as claimed in claim 9, characterised in that the display means

comprises a liquid crystal vehicle registration number display means.

11. A system as claimed in claim 10, characterised in that it comprises a lambertian light source arranged to provide back illumination for the display means.

12. A system as claimed in any one of claims 9 to 11, characterised in that it is

adapted for the display means to exhibit a display that is characteristic of the vehicle

being stolen or otherwise in an unauthorised state.

13. A system as claimed in any one of claims 9 to 11, characterised in that it is adapted for the display means to exhibit a display indicating that the vehicle is stolen or otherwise in an unauthorised state.

14. A system as claimed in claim 12 or 13, characterised in that it is adapted for the display means to exhibit a vehicle registration number display in addition to the unauthorised state display.

15. A system as claimed in claim 14, characterised in that it is adapted for the display means to exhibit the two displays alternately.

16. A system as claimed in any one of claims 12 to 15, characterised in that the unauthorised state display comprises a substantial area of opacity.

17. A system as claimed in claim 16, characterised in that the display means

comprises a permanent display of the vehicle registration number, a substantial area of which is covered by said area of opacity.

18. A system as claimed in claim 16 or 17, characterised in that said area of opacity comprises a substantial area of the vehicle's windscreen.

19. A system as claimed in any one of claims 12 to 18, characterised in that the

unauthorised state display comprises the word "stolen" or the like.

20. A system as claimed in any one of claims 12 to 19, characterised in that it comprises means adapted to respond to an authorisation signal to prevent exhibition

of the unauthorised state display.

21. A system as claimed in any one of claims 12 to 19, characterised in that it comprises means adapted to respond to an authorisation signal to suppress exhibition of the unauthorised state display.

22. A system as claimed in any one of claims 12 to 21, characterised in that it comprises means adapted to respond to a vehicle ignition detection signal and the absence of an authorisation signal to enable exhibition of the unauthorised state display.

23. A system as claimed in claim 22, characterised in that the display control means comprise means adapted to enable exhibition of the unauthorised state display only above a predetermined threshold speed of the vehicle.

24. A system as claimed in any one of claims 9 to 23, characterised in that the

security control means comprises a security switch adapted to respond to operation thereof to transmit an authorisation signal to the display control means.

25. A system as claimed in any one of claims 9 to 23, characterised in that the security control means comprises a touch pad or other keyboard adapted for the input

of an authorisation code and in response to transmit an authorisation signal to the display control means.

26. A system as claimed in claim 24 or 25, characterised in that it is adapted for the authorisation signal to be coded.

27. Display means, vehicle security means or a vehicle security system, substantially according to any example hereinbefore described.

28. Display means, vehicle security means or a vehicle security system, substantially according to any example hereinbefore describe with reference to and

illustrated in the accompanying drawings.

29. A vehicle, characterised in that it comprises means or a system as claimed in any one of claims 4 to 28.