WO2025195539A1

WO2025195539A1 - Side-emitting safety element

Info

Publication number: WO2025195539A1
Application number: PCT/CZ2025/050024
Authority: WO
Inventors: Marketa KRALOVA; Vit Ledl; Romana KRALOVA
Original assignee: SCILIF SRO
Current assignee: SCILIF SRO
Priority date: 2024-03-20
Filing date: 2025-03-14
Publication date: 2025-09-25
Anticipated expiration: 2026-09-20
Also published as: CZ37926U1

Abstract

The invention relates to a side-emitting safety element, which comprises a light guide (1) and at least one light source fixedly or detachably connected to one end of the light guide (1), wherein the light guide (1) is along at least part of its length provided with a perforated protective cover (2) made of heat and flame-resistant material, wherein the area of each individual through hole (20) in the protective cover (2) is 0.1 to 6 mm² and the area of the through holes (20) represents 0.5 to 50 % of the area of the protective cover (2) of the light guide (1).

Description

Side-emitting safety element

Technical field

The invention relates to a side-emitting safety element with increased protection of a light guide against heat and flames.

Background art

Currently, side-emitting safety elements designed to ensure the visibility of persons or objects in poor lighting conditions, e.g. in road traffic, or during the intervention of rescue and/or security forces, etc., are known and available on the market. Thanks to their active light emission, these safety elements outperform previous retro-reflective elements which only passively reflect incident light radiation, the effectiveness of which is in some situations significantly limited.

For example, CZ 28462 discloses an active safety clothing element which comprises a connection to a light source and a light guide which is enclosed in a textile coating. This coating protects the light guide from mechanical damage, serves to attach it to clothing or another textile product, and at the same time creates diffuse scattering of the light emitted by the light guide, wherein according to experiments, the diffusely scattered light is more visible and uniform than the light emitted by the light guide itself without a textile coating. The textile coating also allows for the creation of various colour effects with sufficient luminosity and visibility.

CZ 28783 describes a linear illumination device of a similar design as the active safety clothing element from CZ 28462, intended for local illumination, or illuminated demarcation of various objects, furniture, buildings, etc., or for creating luminous signs.

EP 2917391 discloses a safety means actively emitting light, comprising a single-fibre light guide housed in a cover formed by a two-dimensional woven textile strip, one edge of which is configured as an integrally woven tube, or alternatively the cover is formed by a ribbon having two edges with an integrally woven tube embedded in the surface of the ribbon between the two edges. The light guide is arranged in the tube.

Existing solutions for these means use light guides based on side-emitting polymer optical fibres (POF), based, e.g., on polymethyl methacrylate (PMMA) or thermoplastic polyurethane (TPU), etc., which are characterized by a low melting point (e.g. PMMA 160 °C, TPU 220 °C). Their disadvantage is that existing textile coatings are not able to provide these light guides with sufficient protection against increased temperature or flames, or radiation or similar phenomena, so that when exposed to increased temperature, e.g. in a fire, these materials quickly soften and the light guide loses its optical function, which is not desirable.

The object of the invention is to provide a side-emitting safety element that does not suffer from the disadvantages of the background art.

Summary of invention

The object of the invention is achieved by a side-emitting safety element comprising a light guide and at least one light source fixedly or detachably connected to one end of the light guide, the principle of which consists in that the light guide is provided along at least part of its length with a perforated protective cover made of heat and flame-resistant material, wherein the area of each individual through hole is 0.1 to 6 mm² and the area of the through holes represents 0.5 to 50 %, preferably 10 to 35 %, of the area of the protective cover of the light guide.

The protective cover of the light guide preferably has a structure of a piping with a side strip along at least part of its length for permanent or temporary attachment of the side-emitting safety element to other objects.

When incorporated into the final product, the protective cover of the light guide may have the form of a tube or a so-called textile tunnel, which is part of this final product, such as clothing, textile strap, etc. Brief description of drawings

In the attached drawing, Fig. 1 is a photograph of a preferred variant of a protective cover of a light guide of a side-emitting safety element according to the invention with perforation formed by uniformly distributed circular holes, Fig. 2 is a photograph of another preferred variant of the protective cover of the light guide of the side-emitting safety element according to the invention with perforation formed by uniformly distributed holes in the shape of a regular hexagon, Fig. 3 is a visualization of the side-emitting safety element according to the invention, wherein the protective cover of the light guide is formed by a piping with a side strip, Fig. 4 is a visualization of the side-emitting safety element according to the invention, which is attached to a base via a side strip of the protective cover, and finally, Fig. 5 is a visualization of different embodiments of the protective cover with different types of perforations.

Description of embodiments

The side-emitting safety element according to the invention comprises at least one (unillustrated) light source for illuminating the light guide and at least one light guide 1_, which is housed with at least part of its length in a protective cover 2 - see, for example, Fig. 3.

The light source is fixedly or detachably connected to one end of the light guide 1_. A suitable light source is, e.g., an LED or laser diode emitting light in the full spectrum (white LED), only in a narrow range of light (coloured LED) or in the UV spectrum. If necessary, a light source emitting in a different spectrum, e.g. infrared (IR), etc., may be used alone or in combination.

The light source is connected to an electric power source consisting of a current controlled circuit and an accumulator or a primary electric cell.

If necessary, two or more light sources can be assigned to one light guide 1_. For example, two or more light sources, preferably emitting in a different spectrum, may be connected to one end of the light guide 1. for simultaneous or separate illumination of the light guide 1_, or at least one light source may be connected to each end of the light guide 1_. The light guide 1_ is a light guide 1_ based on side-emitting polymer optical fibres, for example based on polymethyl methacrylate (PMMA) or thermoplastic polyurethane (TPU). If a light guide 1. with a circular cross-section is used, its diameter is preferably 0.25 to 20 mm, more preferably 0.5 to 10 mm; if a light guide 1. with a different cross-sectional shape is used, e.g. rectangular, the length of its (longest) side is preferably up to 20 mm. In order to mitigate the decrease in the intensity of the emitted light along the length of the light guide 1_, the light guide 1. may be provided at the opposite end to that to which the light source is connected with some known means for reflecting at least part of the light back into the light guide 1_. Such means is, for example, a mirror surface.

If a light source emitting in the UV spectrum is used, a luminophore is arranged on at least part of the surface of the light guide 1. for converting the UV light into visible spectrum. Two or more luminophores of different colours may be combined within a single light guide 1. to achieve coloured lighting effects.

The protective cover 2 of the light guide 1. is made of a material resistant to heat and flames, wherein the area of each individual through hole 20 therein is 0.1 to 6 mm² and the area of the through holes 20 represents a total of 0.5 to 50 %, preferably 10 to 35 %, of the surface area of the protective cover 2. The material of the protective cover 2 provides the light guide 1_ with protection against temperature up to 400 °C. Figure 1 is a photograph of a preferred embodiment of the material of the protective cover 2 of the light guide 1. of side-emitting safety element with perforations formed by regularly arranged circular holes 20 having a diameter of 0.8 mm uniformly distributed over the entire area of the protective cover 2, the area of which represents approximately 10 % of the surface area of the protective cover 2. Fig. 2 is a photograph of another preferred variant of the protective cover 2 of the light guide 1_ of the side-emitting safety element with perforations consisting of regularly arranged holes 20 in the shape of a regular hexagon with a side length of 0.8 mm, uniformly distributed over the entire area of the protective cover 2, the area of which represents approximately 28 % of the surface area of the protective cover 2. In general, the holes 20 in the protective cover 2 can have any shape. Optionally, the shape and/or size and/or density of the holes 20, or the proportion of the surface area formed by the through holes 20, may vary as required along the length and/or circumference of the protective cover 2 - see, for example, Figure 5, which shows, for illustrative purposes, visualisations of various embodiments of the protective cover 2 with different distributions and sizes of the holes 20.

The material of the protective cover 2 may have the form of a perforated foil/film or a fibrous layer, wherein the perforations are wholly or at least partially formed by the structure of this layer. Suitable flexible heat and flame resistant materials include:

- viscose modified with flame retardant (containing organophosphorus and nitrogen/sulphur-containing substances)

- polyester with at least one organophosphorus substance incorporated in its structure (e.g. material with the trade name Trevira)

- modacrylic

- meta-aramid (e.g. material with the trade name Nomex or Conex or Kermel)

- para-aramid (e.g. material with the trade name Kevlar or Twaron)

- polybenzimidazole (PBI)

- phenylenebenzobisoxazole (PBO - e.g., material with the trade name Zylon)

- cotton the surface of which is treated with a flame retardant (FR inhibitor) containing organophosphorus and nitrogen monomers or reactive forms

- a cotton and polyester blend, the surface of which is treated with a flame retardant containing organophosphorus and nitrogen monomers or reactive forms

- wool, the surface of which is treated with a flame retardant containing organophosphorus and nitrogen monomers or reactive forms

- a wool and polyester blend, the surface of which is treated with a flame retardant containing organophosphorus and nitrogen monomers or reactive forms

- a strip of any of the above-mentioned materials coated with polytetrafluoroethylene (PTFE) with glass particles embedded on the surface or in the internal structure (in addition, the glass particles provide the material with retro-reflective properties)

- a strip of any of the above-mentioned materials coated with polyurethane (Pll) with glass particles embedded on the surface or in the internal structure (in addition, the glass particles provide the material with retro-reflective properties)

- graphene

- non-textile refractory composite materials based on activated carbon or graphene (graphene X).

The protective cover 2 thus formed, thanks to its properties, especially its flexibility, does not in any way restrict the bending of the light guide 1_and thus also its application.

The light emitted by the light guide 1_ passes through the holes 20 in the protective cover 2; the protective cover 2 provides the light guide 1_ with sufficient protection from the effects of elevated temperatures and flames. The area of the through holes 20 represents 0.5 to 50 %, preferably 10 to 35 %, of the surface area of the protective cover 2, whereby the through holes 20 ensure the passage of a sufficient amount of light out of the protective cover 2. At the same time, diffuse scattering of the emitted light occurs, the diffuse scattered light being more visible and more uniform than the light emitted by the light guide as such without the protective cover 2. Even in the case where the surface area of the through holes 20 of the perforation represents up to 50 % of the surface area of the protective cover 2, the cover 2 as a whole provides sufficient resistance to heat and flames for the light guide 1_. If desired, the protective cover 2_may be provided with a retro-reflective layer on at least one of its surfaces. In the case where the retro-reflective layer is deposited on the inner surface of the protective cover 2, the luminous flux which passes through the through holes 20 in the protective cover is higher than if the protective cover 2 is not provided with this retro- reflective layer - part of the light emitted by the light guide 1. is reflected from the inner surface of the protective cover 2 into the through the holes 20 and exits through them out of the protective cover 2. In the case where the retro-reflective layer is deposited on the outer surface of the protective cover 2, it also provides the side-emitting safety element with retro-reflective properties in addition to its active radiation. The retro-active properties are particularly suitable for emergency cases of reduced luminous intensity of the light guide 1_, of a discharged power source, or for a transitional period when the light source of the side-emitting safety element has not yet been activated. Retro-reflective or other materials, e.g. in the form of strips, meeting the standard for increasing the retro- reflective effect may be used in conjunction with this solution; these materials may be integrated in/on the protective cover 2 of the light guide 1. or may form separate structures.

The protective cover 2 may be in the form of piping, where the hollow portion 21 for housing the light guide 2 is provided along at least part of its length with a side strap 22 for permanently or temporarily attaching the side-emitting safety component to other objects, e.g. garments, equipment components, etc. - see Figures 3 and 4. This side strip 22 may or may not have the same perforations as the hollow portion 21 of the protective cover 2.

In another embodiment, the protective cover 2 of the light guide 1. is directly part of the garment or an accessory component, for example in the form of a fabric tunnel or tube.

The side-emitting safety element according to the invention is particularly useful for the illumination of persons or objects for safety purposes in environments with high temperature or radiation or such a risk, e.g., it may be part of the clothing or equipment of firefighters, rescue workers, workers in the mining industry, workers at airports, workers in operations with fire or explosion hazards, etc.

Claims

1. A side-emitting safety element comprising a light guide (1 ) and at least one light source fixedly or detachably connected to one end of the light guide (1 ), characterized in that the light guide (1 ) is along at least part of its length provided with a perforated protective cover (2) made of heat and flame-resistant material, wherein the area of each individual through hole (20) in the protective cover (2) is 0.1 to 6 mm², the area of the through holes (20) representing 0.5 to 50 % of the area of the protective cover (2) of the light guide (1 ).

2. The side-emitting safety element according to claim 1 , characterized in that the area of all the through holes (20) represents 10 to 35 % of the area of the protective cover (2) of the light guide (1 ).

3. The side-emitting safety element according to claim 1 , characterized in that the protective cover (2) of the light guide (1 ) is piping provided with a side strip (22) along at least part of its length (22).

4. The side-emitting safety element according to claim 1 , characterized in that the protective cover (2) of the light guide (1 ) is a tube.

5. The side-emitting safety element according to claim 1 , characterized in that the protective cover (2) of the light guide (1 ) is a textile tunnel.

6. The side-emitting safety element according to claim 1 , characterized in that the material of the protective cover (2) is a textile material selected from the group comprising:

- viscose modified containing organophosphorus and nitrogen/sulphur- containing substances;

- polyester with at least one organophosphorus substance incorporated into its structure;

- modacrylic

- meta-aramid;

- para-aramid; - polybenzimidazole;

- phenylenebenzobisoxazole;

- cotton, the surface of which is treated with a flame retardant containing organophosphorus and nitrogen monomers or reactive forms

7. The side-emitting safety element according to claim 1 , characterized in that the material of the protective cover (2) is a material the form of a perforated foil/film selected from the group comprising:

- a strip coated with polytetrafluoroethylene (PTFE) with glass particles embedded on the surface or in the internal structure;

- a strip coated with polyurethane (Pll) with glass particles embedded on the surface or in the internal structure;

- graphene;