GB2245699A - Lighting display arrangement - Google Patents

Abstract

A display uses a number of flashing lamps 1 or reflecting devices distributed along a cable which can be festooned for decorative or other purposes, the lamps being switched by control elements 3 in a random manner so that a twinkling effect is produced. A means is provided to both house the light emitting device and connect to the cable in an affordable manner. <IMAGE>

Description

Lighting Display Arrangement This invention relates to a lighting display arrangement incorporating a number of lighting elements, eg incandescent lamps, which are required to operate intermittently, and in particular, flash, either randomly (or at least subjectively randomly) or in some regular manner.

Displays employing incandescent lamps or other light emitting or reflecting devices are used for decoration, or to attract attention to a sales display for example. The lamps are provided in a string of two or more intermittently activated units which are operated in such a manner that a randomly flashing or twinkling effect is produced. The units normally operate n a manner whereby: (a) all units are switched on or off together; (b) power or control is supplied via three or more control lines to obtain the effect of a flow of light in one direction, multiple lights being connected to each line; or (c) units are supplied with power using individual power cables so that they may be controlled independently in a random fashion as required.

Such systems suffer from limitation of the flashing effects which may be produced because of the number of control wires needed.

One object of the present invention is to provide a lighting display with a large measure of versatility in the patterns available from a limited number of control wires.

According to the present Invention a lighting display arrangement comprises a plurality of lighting elements controlled by respective control circuit elements, the control circuit elements having a serial connection whereby a logic pulse pattern can be passed serially through the control circuit elements to cause corresponding actuation of the lighting elements.

The lighting elements may be light sources adapted to be switched on and off In correspondence with the pattern.

Alternatively, the lighting elements may be secondary elements adapted to control light emission from respective primary elements.

Again, the lighting elements may be electronically switchable reflectors or transmission elements.

There is preferably a logic pattern generator serially connected to the control circuit elements which constitute a distributed shift register.

Each lighting element and its associated control circuit element are mounted in a respective common housing.

A serial connection between the lighting elements is preferably provided by a cable housing a plurality of conductors to which connection is made by insulation displacement connectors within the housing, the housing being adapted to make such connection on clamping the housing on to the cable.

The pattern generator may be a pseudo-random pattern generator or may comprise a logic look-up table.

One example of a lighting display arrangement according to the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 is a schematic diagram of a plurality of lights and their connection in the display arrangement; and Figure 2 is a diagram of one lighting element and its printed circuit connections to a supply cable.

Referring to Figure 1, a series of incandescent lamps 1, of which there may be tens or hundreds, are supplied by driver amplifiers 3, each driver being controlled by a respective stage 5 of a shift register, ie a logic element which can adopt a '1' state or a '0' state. Each stage of the shift register is controlled by an input 7 from the preceding stage and a clock input 9 fed In parallel to all stages. The output 11 of each stage 5 is connected serially to the input, 7, of the next. Thus, at each clock pulse a particular stage 5 takes up the state of the preceding stage and the associated driver 3 is activated or not according as the stage acquires a '1' state or a '0' state.A 1/0 pattern will thus travel down the shift register at a rate determined by the clock pulse frequency and each lamp will light for the duration of each clock pulse period for which the associated register stage has a '1' state.

The pattern that is shifted through the register is produced by a pattern generator 13. The range of patterns required for different applications is very wide and may include anything from all-on, all-off, at regular intervals to a completely random on-off pattern. In this particular example it is assumed that random switching is required. The pattern generator may then be a shift-register with interstage feedback which can produce a pseudo-random binary pattern of very great length compared to the register length. Such pseudo-random pattern generators are well known.

In this lighting display application it may be undesirable that the pattern should contain an excessive sequence of the same binary digit - as may well occur in the ordinary course of events.

In this case a check may be made on, say, the last five stages of the pattern generator (or in a separate register devoted to this purpose) so that a reversal can be forced on the sixth bit if five of the same bit occur in succession.

Other forms of pattern generator, eg a look-up table, may be employed, more suited to particular patterns.

The pattern generator - 13 is located at a convenient control station which has a power source. It is connected to feed a cable 15 which has four conductors: a power line 17 which may be at, say, 12 volts D.C.; a zero voltage line 19 providing a return path; a clock pulse line 21 connected to a clock pulse generator in the circuit 13; and a pattern data line 23. The cable 15 extends throughout the display from each lamp unit to the next. The data line 23 is connected to each register stage 5 in series to produce the shift register already explained. The clock pulse line 21 is also fed to each stage 5 in series although a parallel feed would be satisfactory if the number of lights and the cable length were not too large to produce differential phase shift between data and clock signal.

The power line 17 provides 'power' for operation of the register stage and also for energisation of the light 1.

Referring now to Figure 2, this shows one complete lighting unit connected to the cable 15. The lighting unit comprises the lamp 1, lamp holder 25, shift register stage 5 and driver 3 incorporated into an integrated circuit 27. The lamp holder 25 is integral with a plastics housing 29 for the whole unit.

Connections between the cable conductors and the integrated circuit 27 are made by conductors of a printed circuit 30 which are fitted with insulation severing connectors 31. The cable 15 Is of ribbon form and is clamped between two parts of the housing 29 on assembly. In so doing, the connectors 31 sever the insulation on the respective conductors and make connection to the conductor. Cutting blades 33 are mounted in the housing 29 so as to completely cut through the data and clock conductors 23 and 21 leaving a serial path through the integrated circuit for these signal lines.

The lamp 1 has a base 35 with contacts which engage spring contacts 37 of the holder 25, which in turn are connected to pads 39 on the printed circuit 30.

The printed circuit 30 and integrated circuit 27 are encapsulated within the housing 29, leaving only the connectors 31 and 33 exposed. The unit is thus completely weatherproof.

While a typical application uses lamps as described above, the invention is equally applicable to electronically controlled optical surfaces, such as liquid crystal devices, which can switch between transparency and opacity or between reflectivity and non reflectivity. Thus, flashing lights may be provided by direct control of the source, as described above, or by secondary control, ie masking, reflecting, of a primary source. The masking facility may, in addition, provide means for displaying information in short spells - flashes - cyclically.

Claims (13)

1. A lighting display arrangement comprising a plurality of lighting elements controlled by respective control circuit elements, said control circuit elements having a serial connection whereby a logic pulse pattern can be passed serially through the control circuit elements to cause corresponding actuation of the lighting elements.

2. An arrangement according to Claim 1, wherein said lighting elements are light sources adapted to be switched on and off in correspondence with said pattern.

3. An arrangement according to Claim 1, wherein said lighting elements are secondary elements adapted to control light emission from respective primary elements.

4. An arrangement according to Claim 3, wherein said lighting elements are electronically switchable reflectors.

5. An arrangement according to Claim 3, wherein said lighting elements are electronically switchable transmission elements.

6. An arrangement according to any preceding claim, including a logic pattern generator serially connected to said control circuit elements which constitute a distributed shift register.

7. An arrangement according to Claim 6, wherein each lighting element and its associated control circuit element are mounted In a respective common housing.

8. An arrangement according to Claim 7, wherein the serial connection between the lighting elements is provided by a cable housing a plurality of conductors to which connection is made by insulation displacement connectors within said housing, the housing being adapted to make such connection on clamping the housing on to the cable.

9. An arrangement according to any of Claims 6, 7 and 8, wherein said pattern generator is a pseudo-random pattern generator.

10. An arrangement according to any of Claims 6, 7 and 8, wherein said pattern generator comprises a logic look-up table.

11. An arrangement according to Claim 9 or Claim 10, including logic means for limiting the number of consecutive occurrences of the same logic element in the logic pattern transmitted to the control circuit elements.

12. A lighting display arrangement substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

13. A lighting display arrangement substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.