LIGHTING APPARATUS FOR HAZARDOUS AREAS

Abstract

A lighting apparatus (102) for hazardous environments, comprising at least one substantially point-like source of light (4), and a housing structure for said at least one substantially point-like source of light, defining at least a triple barrier protective encapsulation (1, 3, 7) to seal and insulate said at least one source of light from the environment, wherein said triple barrier protective encapsulation is at least partially optically transmissive to enable light propagation from said at least one source of light to the environment at predefined wavelengths.

Claims

1. A lighting apparatus for hazardous environments, comprising at least one substantially point-like source of light, and a housing structure for said at least one substantially point-like source of light, defining at least a triple barrier protective encapsulation, the at least triple barrier encapsulation comprising an outer tube, an inner tube, and a fully encapsulating core material element inside the inner tube to completely seal and insulate the at least one source of light and at least one of an electrical board and electrical contacts from the environment, wherein said triple barrier protective encapsulation is optically transmissive to enable light propagation from said at least one source of light to the environment at predefined wavelengths.

2. The apparatus of claim 1, wherein the outer tube and the inner tube of the triple barrier encapsulation are provided as hollow, nested elements.

3. The apparatus of claim 1, wherein the outer tube is configured as an optically transmissive outer element to define a first barrier of insulation against the environment.

4. The apparatus of claim 3, wherein the outer element incorporates a functional coating.

5. The apparatus of claim 1, wherein the inner tube is configured as an optically transmissive inner element to define a second barrier of insulation against the environment.

6. The apparatus of claim 1, wherein any barrier element (1, 3, 7) comprises a number of optically functional features for controlling light, said features optionally comprising surface relief structures.

7. The apparatus of claim 1, wherein the optically functional features have at least one optical function selected from the group consisting of: light directing, collimation, diffusing, coloring, scattering, and distribution function.

8. The apparatus of claim 1, wherein the triple barrier encapsulation comprises at least one material selected from the group consisting of: glass, ceramic, plastic, polymer, and substantially UV resistant material.

9. The apparatus of claim 1, wherein the core material element within the housing structure is defined with an optically transmissive, molded core material encapsulating the at least one substantially point-like source of light to define a third barrier of insulation against the environment, the core material element being configured to support the at least one substantially point-like source of light.

10. The apparatus of claim 9, wherein the core material defining the core material element is selected from the group consisting of: elastomer, silicone, acrylic, polyurethane, olefin based elastomer, and polymer.

11. The apparatus of claim 9, wherein the core material element is configured for color tuning or light extraction.

12. The apparatus of claim 1, comprising at least one detachable closing element at each end of the inner tube and the outer tube within the housing.

13. The apparatus of claim 12, wherein the closing elements include a number of electrically conductive portions or elements for supplying power to said at least one substantially point-like source of light.

14. The apparatus of claim 1, wherein said at least one substantially point-like source of light includes a LED (light-emitting diode).

15. The apparatus of claim 1, wherein said at least one substantially point-like source of light includes a LED strip of a plurality of LEDs.

16. The apparatus of claim 1, comprising a cooling element for said at least one source of light.

17. The apparatus of claim 5, wherein a gap of gaseous substance such as air remains between the inner tube element and the outer tube element.

18. The apparatus of claim 12, wherein the closing element is a lid, flap, or end gap.

19. The apparatus of claim 4, wherein the functional coating disposed on the outer tube comprises an electrically conductive coating.

20. The apparatus of claim 1, wherein the optically functional features comprise at least one of a three-dimensional sub-micron scale profile and a three-dimensional micron scale profile.

21. The apparatus of claim 1, wherein the surface relief structures are defined as three-dimensional relief forms on the surface and/or embedded within the material to establish a desired light distribution.

22. The apparatus of claim 12, wherein the closing elements are configured to hermetically seal the housing structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Next the invention will be described in greater detail with reference to the accompanying drawings, in which:

[0029] FIG. 1 illustrates an embodiment of a lighting apparatus in accordance with the present invention.

[0030] FIG. 2 illustrates the internals of the embodiment of FIG. 1 with the cover element removed.

DETAILED DESCRIPTION

[0031] FIG. 1 illustrates, by way of example only, an embodiment of a lighting apparatus 102, or ‘light fixture’ or ‘luminaire’, in accordance with the present invention. On the right at 110, a cross-sectional view along line A-A is shown. The apparatus 102 comprises housing with an outer element 7 essentially defining in this example a symmetrical cover tube that may optionally be electrically conductive to fulfil ‘Ex’-area utilization criteria and requirements, for instance.

[0032] Base material of the outer tube 7 may include e.g. transparent glass, ceramic or polymer with or without special conductive coating. The used materials are preferably UV (ultraviolet) resistant.

[0033] Both end areas of the cover tube 7 are preferably hermetically sealed, optionally with an end cover such as a lid or cap possibly also carrying electrical rod or wired contacts 6 to enable energizing the light sources and potential related control electronics within the housing, essentially organized e.g. as a LED (light-emitting diode) strip 4 in this particular embodiment. The end cover may be, after manufacturing, permanently sealed or remain removable/operable, with or without tools, to facilitate serviceability of the internals of the luminaire.

[0034] FIG. 2 illustrates the internals of the embodiment of FIG. 1 with the tubular outer cover element 7 removed.

[0035] Within the hollow space defined by the cover element 7, the inner element, preferably being or comprising a tube 1, is disposed. It may include e.g. transparent glass, ceramic or plastic material 2, which may inherently have or be specifically configured to carry optically functional characteristics for light control. It may exhibit optical management features such as three dimensional relief forms on the (inner/outer) surface and/or as embedded within the material for purposes such as light directing, collimation, diffusing, coloring (e.g. from white light), and/or generally establishing a desired light distribution. These functionalities can be fully integrated with the tube and/or assembled at close proximity thereto, either on the inside or outside. The optical features can be realized by refractive and/or diffractive surface reliefs, volume/cavity optics containing e.g. sub-micron or micron scale profiles, or volume scattering features. In addition to or instead of such features of the inner tube 1, in some embodiments the cover element 7 may incorporate similar characteristics.

[0036] Inside the tube 1, at least one light source is found e.g. in the form of one or a plurality of LED strips 4. The LEDs may be traditionally packaged ones or e.g. OLEDs (organic LED). Alternatively or additionally, some other applicable light sources could be applied. Source-emitted or finally outcoupled color is typically white, but basically any color/wavelength is possible including IR radiation. Light source may be provided with related substrate, control electronics and/or other assisting elements such as strip or sheet for cooling purposes.

[0037] Light source 4 is preferably fully encapsulated and sealed by a covering hermetic barrier (core) element or layer 3 that is sufficiently transparent with high enough transmittance according to the utilized criteria depending on the embodiment, and may implement color tuning and/or improve light extraction from the source 4, for example. Suitable materials and shapes, optionally reliefs, may again be used for optimized light transmission and control together with hermetic sealing and protection function. Encapsulating material may especially include silicone, polyurethane, acrylic, olefin based elastomer, or polymer, i.e. applicable material to avoid electric short circuits, sparks, and/or moisture contacts. The material may be solid or gel-like, for instance. It may be moldable, extrudable and/or curable during the manufacturing of the lighting apparatus.

[0038] The inner tube 1 may be finally sealed with permanent or detachable/operable (with or without tools) end covers such as caps 5a, 5b, which may contain e.g. rod or wired contacts for electrically connecting the light source 4 to the external power supply.

[0039] The caps of the inner 1 and cover (outer) 7 barrier tube elements may be shared or dedicated depending on the embodiment. The caps may lock the inner tube 1 in place within the cover tube 7.