GB2347487A

GB2347487A - Visibility enhancement device

Info

Publication number: GB2347487A
Application number: GB0001541A
Authority: GB
Inventors: John Mason
Original assignee: LUMOLITE Ltd
Current assignee: LUMOLITE Ltd
Priority date: 1999-03-05
Filing date: 2000-01-25
Publication date: 2000-09-06
Also published as: GB0001541D0; GB9905151D0

Abstract

A visibility enhancement device 1 including at least one light emitting diode (LED) 3 and a power supply 2 therefor. The power supply 2 is configured so as to cause the LEDs to flash intermittently. The LEDs are disposed adjacent a support layer 8 having a retroreflective material 10 associated therewith. The LEDs are disposed in a tubular waterproof transparent plastics material. The device may be in the form of a single strip which can be worn by a pedestrian or incorporated into a garment or emergency apparel. This device may also be used to illuminate hazard warning triangles used by motorists.

Description

VISIBILITY ENHANCEMENT This invention relates to visibility enhancement, and it relates more particularly to devices that can either be worn by, or attached to the clothing of, persons liable to find themselves in circumstances, perhaps of personal danger, in which the extent of their visibility may be of great significance with regard, for example, to their chances of being rescued, or used by persons such as motorists who are aware of, or in charge of, an obstruction (such as a brokendown vehicle) in a potentially dangerous and/or unexpected location to warn others.

In this respect, various devices such as belts, jackets, shoulder straps and warning triangles incorporating highly reflective and/or fluorescent materials are known, but such devices are of limited effectiveness since they are, in essence, passive devices dependent for their visibility upon external illumination, either naturally occurring or otherwise.

In order to significantly enhance visibility, therefore, it has been proposed to incorporate in such devices active light generating means, but difficulties are encountered in respect, for example, of the need to ensure that such devices and/or power supplies therefor are sufficiently rugged and are adequately protected from the hostile environments in which they may find use. It has been proposed in this respect to utilise electroluminescent devices but, though rugged, these require high voltage power supplies which are not always readily available and moreover can cause problems, for example, when exposed to water.

It is an object of the invention to provide a visibility enhancing device with active light emission that addresses at least one of the foregoing difficulties.

According to the invention there is provided a visibility enhancing device incorporating at least one light-emitting diode (LED) and a power supply therefor; the power supply being configured so as to cause the or each LED to flash intermittently at a rate of ten Hz or less; the or each LED being disposed adjacent a support layer and having a retroreflective material associated therewith.

Preferably, the at least one LED is housed in a tube made, for example, of unreinforced PVC, and the retroreflective material is hollow and can accommodate the or each LED therewithin. This permits the retroreflective material to be lit by the or each LED whilst protecting the retroreflective material from damage by direct LED contact.

Preferably the device takes the form of a multilayered laminate, with the support layer comprising a webbing stip or a plastics tray and the overlayer being a relatively thin transparent and waterproof layer. Preferably also, the power supply is housed in a water-resistant container.

In a further preferred construction, the or each LED is disposed between the support layer and a protective overlayer transmissive of light generated by the or each LED.

It is further preferred that the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 5 Hz or less, and still further that the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 1.088 Hz.

If desired, the power supply may comprise a further LED caused to flash intermittently by an in-built integrated circuit, and constrained to illuminate a photosensitive device connected to operate the first-mentioned LED or LEDs.

In one preferred embodiment the device comprises a single strip, the ends of which can be releasably secured together to allow placement over one shoulder and under the opposite arm of a human user and attachment in that position.

In another preferred embodiment, the device comprises a warning triangle with at least one LED disposed in each limb thereof.

In order that the invention may be clearly understood and readily carried into effect, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows in perspective schematic view, devices in accordance with an example of the invention, Figure 2 shows a cross section through the example of Figure 1, Figure 3 shows a typical operating circuit and power supply, Figure 4 shows schematically an alternative operating circuit layout, and Figure 5 shows a warning triangle in accordance with another example of the invention.

Referring now to Figure 1, a device in accordance with one example of the invention is shown at 1. The device 1, in this example, takes the form of a laminated strip, the construction of which will be described more fully with reference to Figure 2, of length 1.23 metres and intended to be worn diagonally across the chest and back of a user as shown. The undersurface of the strip at one end thereof and the top surface at the other end are furnished with corresponding areas 2 of the material known as"Velcro" (RTM) which are intended to be pressed together so as to hold the strip in place over one shoulder of the user and under the opposite arm. Clearly, additional or alternative techniques may be employed if desired to secure the ends of the strip 1 together and/or to secure the strip to the user's outer garment.

The strip 1 is provided with a plurality of light emitting diodes (LEDs) of which, in this example, four (3,4,5 and 6) are included in that part of the strip 1 which overlies the user's chest, and thus faces forwardly in the Figure, and four (not shown) are included in the part of the strip which overlies the user's back, and thus faces rearwardly. The LEDs are overlain by a protective and waterproofing layer 7 which is at least translucent, and preferably transparent to the light emitted by the LEDs.

Referring now to Figure 2, which represents a cross-section taken on arrows II-II of Figure 1, the strip 1 is of laminar construction and is founded on a support layer 8 of webbing or other material of adequate strength and durability. The LEDs such as 5 are enclosed in a common, clear tube 9 of unreinforced PVC and the LEDs, in their tube, lie upon or are enclosed within retroreflective material 10 of generally hollow configuration, depending upon the particular form of construction favoured, but in any event being covered by a clear plastics laminate constituting the outer protective and waterproofing layer 7. The principal objectives of using the PVC tube and the retroreflective wrap are to assist in spreading the emitted light, so as to illuminate substantially the whole belt, and to protect the retroreflective material from being punctured by the LEDs.

The layer 7 is of plastics material and may be applied to the strip in any convenient manner, such as by ultrasonic welding or other sealing or fusing procedures well known in the plastics industry. Alternatively, the layer 7 may enwrap the entire strip and be secured to itself by localised heating, for example.

Part or all of that surface of the support strip 8 which faces the LEDs may be rendered reflective and/or fluorescent if desired. Moreover, if desired, the strip 1 may be supplemented with a belt 12 of similar construction but without the LEDs.

The LEDs are connected in parallel, ensuring that the failure of one does not result in failure of the entire illumination of the belt, and they are preferably operated under the control of a circuit such as that shown in Figure 3, which is effective to flash them on and off at a frequency of 10 Hz or less ; preferably 5 Hz or less and most preferably 1.088 Hz.

The frequency of flashing is preferably fixed, and the LEDs preferably flash in unison to maximise their visibility and attention-attracting potential. Other arrangements may, however, be used if preferred, though it is important to bear in mind the two critical factors of effective visibility enhancement and battery conservation. It has been found in practice that the flashing of LEDs in unison at the aforementioned frequency of 1.088 Hz and a 1: 1 mark-space ratio is extremely effective form both aspects and that, with regard to battery life, can exhibit some 85 hours of operation from one PP3 9-volt battery.

An example of a circuit capable of operating the LEDs in the preferred manner is shown in Figure 3, though it will readily be appreciated that any convenient driving circuit can be used; typical component types and values being incorporated in the following table:

COMPONENT No. VALUE/TYPE RESISTOR R1 124k RESISTOR R2 470k CAPACITOR C1 3. 3 microfarads DIODE Dl IN4TFM146 MICROPROCESSOR M 555 TRANSISTOR T1 BC547 RESISTOR R3 10 I The circuit of Figure 3 is preferably enclosed within a case, in this example a rectangular case of dimensions 35mm by 45mm by 20mm, which is at least water resistant and may be waterproofed to a given extent if desired, bearing in mind the principal intended use for the device. The case preferably contains an externally operable on/off switch, enabling the user to control operation so as, for example, to avoid wasting battery power when the ambient conditions are such that illumination of the LEDs of the device would be of little benefit. The switch may conveniently be made such as to turn on automatically when exposed to water.

If desired, the battery used to drive the circuit may be rechargeable, and/or it may be or include a solar cell. As a further alternative, the circuit of Figure 3 could be replaced by a simplified circuit based upon the use of an LED with a built-in integrated circuit which can be flashed on to a photosensitive device that, in turn, triggers the LEDs in the strip 1.

An alternative circuit layout is represented schematically in Figure 4; the layout being founded upon a printed circuit board supporting a similar eight-terminal integrated circuit (IC1) to that (M) described with reference to Figure 3 and a transistor like T1. As indicated in Figure 4, however, the peripheral components and connections are simplified, with the components R1 and D1 being connected in parallel between terminals 6 and 8 of IC1 (Dl positive to terminal 6) and capacitor Cl across terminals 2 and 8 (positive to terminal 2). The collector, base and emitter terminals of the transistor are marked C, B and E respectively and terminals C and B are connected to terminals 4 and 8 respectively of IC1. The LEDs are connected between terminal 5 of IC1 and terminal E of the transistor (positive to terminal 5 of IC1), and finally the battery is connected across terminals 5 and 4 of IC1 (positive to terminal 5).

Figure 5 shows a warning triangle intended for use as a warning device by persons such as motorists who may, for example, come across, or be in charge of, a vehicle that has broken down in a dangerous or otherwise vulnerable location.

The construction of the triangle 20 is similar to that of the device 1 shown in Figures 1 and 2, except that the support layer 8 of the earlier example is replaced by a triangular formation 21 the limbs of which are formed by plastics trays 22,23 and 24. The formation 21 may be part of a solid triangular sheet of plastics material, or may constitute an apertured triangle consisting solely of the trays 22-24, which may be fixedly connected together or relatively pivoted so as to render the triangle collapsible for storage, but in any event the trays hold retroreflective material and parallel-connected LEDs mounted in tubes as described in relation to Figures 1 and 2. There may or may not be a protective membrane or sheet over the illuminated surface of the triangle.

In a preferred embodiment, nine LEDs such as 26 are distributed around the triangle, three in each limb; all nine being connected electrically in parallel and driven substantially as described with reference to Figure 3 and/or Figure 4. As before, the LEDs are mounted in protective tubing, but in this embodiment the LEDs of a respective limb such as 22 of the triangle 20 may be located in a respective tube such as 27 for that limb; electrical connections as at 28 being made between the LEDs of different tubes.

Alternatively, a single, suitably shaped and configured, tube may house all nine LEDs. As a further alternative, individual short lengths of tubing can be provided for the respective LEDs.

In one practical example, two AA 1.5 volt batteries have proved sufficient to run the device 20 continuously for a period of 250 hours at an operating frequency of 1.088 Hz.

Reflective material (not shown) may be incorporated in the trays 22-24 if desired to further enhance the visibility of the triangle 20. Moreover, the components of the electronic drive circuit can be disposed behind any of the limbs 2224; preferably the base limb 24, or they can be located in a housing 25 shaped and configured to allow the triangle 20 to stand stably on a reasonably flat surface. Alternative arrangements are however possible, and there is in principle no need for the drive circuit to be permanently attached to the triangle.

Typical dimensions for length and width of each of the limbs such as 22 are 438.35mm and 55. Omm respectively, though other dimensions can of course be used without departing from the scope of the invention.

It will be appreciated that the actual form taken by the device will be determined at least in part by its primary intended role and, for example, whether it is intended for use as a general purpose device or whether it is intended for use with a particular garment or piece of equipment, or to be stowed, when not in use, in a particular vehicle. The device may be incorporated into an outer garment such as a thermal suit or into emergency equipment such as a life-jacket, or may be used separately. If the device is intended for stowage in a particular vehicle, or for use with a particular garment or piece of equipment, that vehicle, garment or equipment may be specially adapted to receive and/or retain the device, and in this respect may carry restraints and/or anchorages therefor.

Claims

CLAIMS 1. A visibility enhancing device incorporating at least one light-emitting diode (LED) and a power supply therefor; the power supply being configured so as to cause the or each LED to flash intermittently at a rate of ten Hz or less; the or each LED being disposed adjacent a support layer and having a retroreflective material associated therewith.
2. A device according to claim 1 wherein the power supply is housed in a water-resistant container.
3. A device according to claim 1 or claim 2 wherein the or each LED is disposed between the support layer and a protective overlayer; at least the overlayer being transmissive of light generated by the or each LED.
4. A device according to any of claims 1 to 3 wherein the retroreflective material is hollow and can accommodate the or each LED therewithin.
5. A device according to any preceding claim configured in the form of a multilayered laminate, with the support layer comprising a webbing stip and the overlayer being a relatively thin transparent and waterproof layer.
6. A device according to any preceding claim including a tubular member of transparent plastics material containing said LED or LEDs.
7. A device according to claim 6 wherein said tubular member is formed of unreinforced PVC.
8. A device according to any preceding claim wherein the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 5 Hz or less.
9. A device according to any preceding claim wherein the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 1.088 Hz.
10. A device according to any preceding claim wherein the power supply comprises a further LED caused to flash intermittently by an in-built integrated circuit, and constrained to illuminate a photosensitive device connected to operate the first-mentioned LED or LEDs.
11. A device according to any preceding claim in the form of a single strip, the ends of which can be releasably secured together to allow placement over one shoulder and under the opposite arm of a human user and attachment in that position.
12. A device according to any of claims 1 to 10 incorporated in a garment or emergency apparel.
13. A device according to any preceding claim including a switch device for selectively connecting the power supply to said at least one LED.

14. A device according to claim 13 wherein said switch device is adapted to automatically connect said power supply to said at least one LED in response to exposure of said switch device to water.

15. A device according to any preceding claim comprising a warning triangle with at least one LED disposed in each limb thereof.

16. A device according to claim 15 wherein the power supply is incorporated in a housing located and configured to enable the device to stand stably.

17. A visibility enhancing device substantially as herein described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A visibility enhancing device incorporating at least one light-emitting diode (LED) and a power supply therefor; the power supply being configured so as to cause the or each LED to flash intermittently at a rate of ten Hz or less; the or each LED being disposed adjacent a support layer and having a retroreflective material associated therewith, characterised by a water resistant tubular member of transparent plastics material containing said LED or LEDs.

2. A device according to claim 1 wherein the power supply is housed in a water-resistant container.

3. A device according to claim 1 or claim 2 wherein the or each LED is disposed between the support layer and a protective overlayer; at least the overlayer being transmissive of light generated by the or each LED.

4. A device according to any of claims 1 to 3 wherein the retroreflective material is hollow and can accommodate the or each LED therewithin.

5. A device according to any preceding claim configured in the form of a multilayered laminate, with the support layer comprising a webbing stip and the overlayer being a relatively thin transparent and waterproof layer.

6. A device according to any preceding claim wherein said tubular member is formed of unreinforced PVC.

7. A device according to any preceding claim wherein the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 5 Hz or less.

8. A device according to any preceding claim wherein the power supply comprises a printed or integrated circuit configured to cause said intermittent operation at a frequency of 1.088 Hz.

9. A device according to any preceding claim wherein the power supply comprises a further LED caused to flash intermittently by an in-built integrated circuit, and constrained to illuminate a photosensitive device connected to operate the first-mentioned LED or LEDs.

10. A device according to any claims 1 to 6 when the duration of each flash is of the order of 20 milliseconds, and the dormant time is of the order of 80 milliseconds.

11. A device according to any preceding claim wherein the or each LED has a candle power of 4000 to 6000 mcp.

12. A device according to any preceding claim in the form of a single strip, the ends of which can be releasably secured together to allow placement over one shoulder and under the opposite arm of a human user and attachment in that position. í3. A device according to any of claims 1 to 10 incorporated in a garment or emergency apparel.
14. A device according to any preceding claim including a switch device for selectively connecting the power supply to said at least one LED.
15. A device according to claim 14 wherein said switch device is adapted to automatically connect said power supply to said at least one LED in response to exposure of said switch device to water.
16. A device according to any preceding claim comprising a warning triangle with at least one LED disposed in each limb thereof.
17. A device according to claim 16 wherein the power supply is incorporated in a housing located and configured to enable the device to stand stably.
18. A visibility enhancing device substantially as herein described with reference to the accompanying drawings.