AU745328B2

AU745328B2 - A linear lighting device having co-extruded internally prismatically scored screens

Info

Publication number: AU745328B2
Application number: AU96432/98A
Authority: AU
Inventors: Roberto Deitinger; Mauro Mazzilli
Original assignee: DA MA Srl
Current assignee: Dama Srl
Priority date: 1997-10-06
Filing date: 1998-10-02
Publication date: 2002-03-21
Anticipated expiration: 2018-10-02
Also published as: AU9643298A; WO1999018390A1; ITRM970601A1; EP1021678A1; IT1295414B1

Description

WO 99/18390 PCT/IT98/00265 A LINEAR LIGHTING DEVICE HAVING CO-EXTRUDED INTERNALLY PRISMATICALLY SCORED SCREENS This invention relates to a linear lighting device provided with co-extruded internally prismatically scored screens.

More particularly, the present invention relates to a device of the above kind that enables a higher brightness under equal radiating energy conditions to be achieved together with a high illumination uniformity and a higher wear resistance, said device being advantageous for application to any linear lighting system, both of the optical guide type and of the continuous illumination type.

It is well known that linear lighting systems are largely utilized for efficient illumination of areas having a substantially linear geometry, such as highway and/or railroad tunnels as well as perimetral sections of areas protected for instance by fences.

Such linear lighting systems can be of optical guide type in which a remote light source is used or of continuous light type, in which, for instance variable power fluorescent lamps are used.

The devices utilized in linear lighting systems of optical guide type are substantially comprised of a conduct having a highly reflecting inner surface, in which a light beam emitted by an optical source, such as a light projector located at an end of said conduit, is propagated. The other end of the conduit can be provided with an optical light recuperator or it can be coupled to another similar device. One or more slits are provided along the side surface of said conduit and are equipped with suitable screens through which the emitted light is diffused to the area to be illuminated.

The devices as used in linear lighting systems of continuous light type substantially differentiate with respect to those described for linear lighting systems of optical guide type owing to the light emission optical system that is formed by a linear light source, such as a fluorescent lamp extending in parallel relation to the axis of said conduit, while the first mentioned systems are provided with a light source located at an end of the conduit.

All above devices have certain drawbacks.

In the first place, aiming at avoiding any glare effects caused by direct view of the light emitted by high power light sources used therein, the screens are generally realized by utilizing suitable opaline materials, generally produced by molding or extrusion of homogeneous mixed raw compositions, so as to make them capable to filter the light, and this entails an average absorbance figure of about 60% of the radiating energy as well as a rapid wear thereof, with resultant increase both in the energy consumption and in the maintenance costs.

A further drawback of the optical guide systems is due to the fact that the screens as utilized therein have a low uniformity figure and, therefore, do not satisfactorily fulfil the illumination uniformity :::requirements in respect of the area to be illuminated, as it is strictly 10 necessary in highway tunnels, and this additionally results in a limitation of the maximum length of the conduits with consequent increase in the linear distribution density of the necessary projectors as well as in the lighting system costs.

A still further drawback of the optical guide systems is due to the fact that the screens used therein have a unhomogeneous transversal photometric solid with respect to the axis of the conduit, thereby creating sharp shadows that could be erroneously construed as obstacles.

The approach proposed by this invention is to be considered in this frame as it enablesall above mentioned problems to be solved.

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Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, :integers or steps.

It is a preferred feature of this invention, therefore, to furnish a device applicable in any linear lighting system and having a higher brightness under equal radiant energy conditions as well as a higher wear resistance, thereby enabling a reduction in power requirements and a reduction in the operation oits to 0e achieved.

It is a preferred feature of this invention to provide a device for optical guide type linear lighting systems having a high, both axial and transversal, illumination uniformity figure.

It is, therefore, specific subject matter of this invention a linear 0: lighting device comprising a tight propagation and/or emission conduit including one or more longitudinal light transmissive portions and one or more non-light transmissive portions, characterized in that said light transmissive portions are provided by corresponding longitudinal slits of a non-light transmissive tubular structure and comprise one or more screens of a co-extruded plastic material including a first inner layer of transparent plastic material, preferably a shock resistant polycarbonate or metacrylate material, and a second outer layer of a plastic material, preferably a polycarbonate or metacrylate material, suitably treated in WO 99/18390 WO 9918390PCT/1T98/00265 3 order to make it opalescent, a prismatic scoring being provided in the inner surface of said transparent layer.

It is further subject-matter of this invention a linear lighting device comprising a light propagation and/or emission conduit including one or more longitudinal light transmissive portions and one or more nonlight transmissive portions, characterized in that said logitudinal non-light transmissive portions are realized by applying upon a light transmissive tubular structure corresponding longitudinal non-light transmissive elements, said light tansmissive tubular structure being made of a coextruded plastic material including a first inner layer of transparent plastic material, preferably a shock resistant polycarbonate or metacrylate material, and a second outer layer of a plastic material, preferably a polycarbonate or metacrylate material, suitably treated in order to make it opalescent, a prismatic scoring being provided in the inner surface of said transparent layer.

Preferably, according to this invention, said prismatic scoring includes triangle shaped, longitudinal or transversal scores.

According to this invention, the construction of this device can be modular.

Further characteristics and embodiments of this invention are recited in the dependent claims.

This invention will be now described by way of illustration rather than by way of limitation according to its preferred embodiments by particularly referring to the Figures of the annexed drawings, in which: Figure 1 is a perspective exploded view of a first device according to this invention, Figure 2 is a front elevation view of a detail of the device of Figure 1, Figure 3 is a cross-section side elevation view of the device of Figure 1, Figure 4 is a cross-section side elevation view of a second device according to the invention, Figures 5a and 5b are cross-section front and side elevation views of the screen of a device according to Figure 4, and Figures 6a and 6b are cross-section front and side elevation views of the screen of a device according to Figure 1.- WO 99/18390 PCT/IT98/00265 4 By referring now to Figures 1-3, it can be observed that a first embodiment of a device 1 according to this invention, adapted for use in linear lighting systems of optical guide type, includes a conduit 2 formed by a substantially cylindrical, tubular structure 20, the inner surface of which reflects the light rays. Said tubular structure 20 is preferably made of aluminium and/or shock resistant polycarbonate and/or metacrylate and its inner surface is made light reflectant by deposition of a polished layer of aluminium with a purity figure 99,95% or by means of a vacuum treatment or by means of a film of reflectant plastic material applied thereon, such as a film of mylar(R) This tubular structure 20 has a longitudinal slit and a screen 3 through which the light can be outwardly diffused is arranged in said slit, as particularly shown in Figure 3. Said longitudinal slit together with screen 3 mounted therein forms the light transmissive longitudinal portion, while said tubular structure 20 forms the longitudinal non-light transmissive portion.

Screen 3, which is particularly novel, will be hereinbelow described.

It should be remarked that the number of slits, as well as their width and their distribution on the surface of said tubular structure 20 can vary without departing from the teachings of this invention.

A first end of conduit 2 is coupled with a projector having a bell shaped construction, preferably made by usual polymer materials as used in technical applications. Bell 4 houses a transversal parabolic diaphram preferably made of a vacuum mirrored thermoplastic material, as well as a lamp 6 arranged upon a circular plate 7 for holding the electrical accessories 8 for power supply of said lamp 6. The parabolic diaphram is adjustably arranged upon plate 7 in order to adjust its focus point with respect to lamp 6, preferably within a range 40 with respect to the axis of lamp 6. Said lamp 6 can be, for instance, a high pressure, metal jodide and sodium, discharge lamp.

The second end of conduit 2 is closed by an optical light recuperator closure member 9 having an inner light reflectant surface, preferably vacuum mirrored and protected by means of polymerized silicone oils, with divergent parabolic optics. The above described device 1 is of modular design, so that one of or both ends of conduit 2 can be coupled to similar conduits 2, rather than to said projector or to said light recuperator closure member 9. Properly shaped gaskets 10 enable light WO 99/18390 PCTIIT98/00265 tight couplings to be achieved between conduit 2 or bell 4 of said projector, respectively, and said light recuperator closure member 9 (or an other conduit 2).

Figure 4 shows a cross-section view of a second embodiment of conduit 2' of a device according to this invention, particularly intended for use in linear lighting systems of continuous illumination type. Said conduit provided with a similar tubular, suitably shaped structure and with a similar screen as in the first embodiment, internally houses a fluorescent, linear lamp 11, arranged at the focus point of a longitudinal parabolic partition 12. Lamp 11 is secured to a plate 13 also acting as a holder member for electrical supply accessories 14. In this case, closure member 9 (not shown) has an inner non-light reflectant surface.

Screens 3 and 3' are made of co-extruded composite plastic material, preferably polycarbonate or metacrylate, which is made shock resistant by means of an integrally embedded reinforcement. This composite material consists of a transparent layer, with a thickness preferably in the range of 2 to 3 mm, having a film of a material coestruded upon its outer surface and suitably treated in order to make it opalescent, for instance of a ultraviolet ray stabilized mixture, with a thickness in the range of 35 to 70 This opalescent film diffuses the light transmitted therethrough thereby suppressing its glaring effects and, as a function of its thickness, as a function of its thickness, as a function of its thickness, it absorbs only within the range of 15% to 40% of the light power irradiated from the lamp.

In addition, said opalescent film imparts brightness to the screen and assures a long useful life, more than 10 years, without incurring the typical yellowing effects of polycarbonate materials.

Screens 3 and 3' are prismatically scored on their inner transparent surface layers.

As it is shown in Figures 5a and 5b, a screen as applied on devices 1 for use in continuous illumination systems, is preferably provided with longitudinal prismatic scoring.

As it is shown in Figures 6a and 6b, a screen 3, as applied on devices 1 for use in optical guide systems, is preferably provided with transversal prismatic scoring in order to enable a better control of the light rays generated by a remote source to be obtained. In fact, said screen 3 is adapted to collect any light rays scarcely divergent at the source and to I WO 99/18390 PCT/IT98/00265 6 control the multiple reflections generated in the above mentioned mirror treated conduit 2, thereby achieving a controlled and constant light in its transversal photometric solid, along a propagation path that can also be more than 10 metres long. Screen 3, which is provided with transversal prismatic scoring with preferably triangle cross-section scores, produces a homogeneous transversal photometric solid, with only light intensity variable as a function of the distance from the projector. In particular, said triangular cross-section shape of its scores is adapted to optimize the light collection capability as a function of the construction characteristics, such as the size, such as the size, of the devices 1 employed in optical guide systems.

Screens 3 and 3' have a good uniformity figure, which is higher than all conventional screens, and, therefore, they are particularly advantageous for application to optical guides. By way of example, a uniformity figure of expressed as the ratio of minimum to maximum illumination intensities is achieved in optical guides having a length of about 6.9 m.

It should be understood that other embodiments of the device according to this invention can be provided with a conduit including a light transmissive tubular structure realized as said screen 3 (or upon which one or more non-light transmissive longitudinal elements are arranged.

In particular, said light transmissive tubular structure is realized of a composite co-extruded plastic material, preferably polycarbonate or metacrylate, which is made shock resistant and, to this end, it is provided with a reinforcement. As above described, such material includes a transparent layer, preferably having a thickness in the range of 2 to 3 mm, upon the outer surface of which a film of a material is co-extruded upon being suitably treated in order to make it opalescent, for instance a mixture stabilized in respect of ultraviolet radiation, with a thickness in the range of 35 to 70 4m. Said light transmissive tubular structure has an intemaly, longitudinally or transversely scored, transparent surface layer.

The above mentioned non-light transmissive elements, realized of shock resistant aluminium, polycarbonate or methacrylate, for instance, are applied to said light transmissive tubular structure internally or extemrnally or by co-extrusion.

WO 99/18390 PCT/IT98/00265 7 Also in respect of linear lighting devices used in optical guide type systems in which the above described light transmissive, tubular structure conduit are arranged, a mirroring treatment is applied to the nonlight transmissive portions of the conduits themselves, in order to enable a multiple reflection propagation of the light radiation.

This invention has been described by way of illustration and not by way of limitation according to its preferred embodiments, but it should expressely be understood that those skilled in the art can make variations and/or changes, without so departing from the scope thereof, as defined in the annexed claims.

Claims

1. A linear lighting device comprising a light propagation and/or emission conduit including one or more longitudinal light transmissive portions and one or more non-light transmissive portions, characterized in that said light transmissive portions are provided by corresponding longitudinal slits of a non-light transmissive tubular structure and comprise one or more screens -of a co- extruded plastic material including a first inner layer of transparent plastic material and a second outer layer of a plastic material, suitably treated in order to make it opalescent, a prismatic scoring being provided in the inner surface of said transparent layer.

2. A linear lighting device comprising a light propagation and/or emission conduit including one or more longitudinal light transmissive portions and one or more non-light transmissive portions, 15 characterized in that said logitudinal non-light transmissive portions are i realized by applying upon a light transmissive tubular structure corresponding longitudinal non-light transmissive elements, said light tansmissive tubular structure being made of a co-extruded plastic material including a first inner layer of transparent plastic material and a second outer layer of a plastic material, suitably treated in order to make it opalescent, a prismatic scoring being provided in the inner surface of said transparent layer.

3. A device according to claim 1 or 2, characterized in that *said transparent plastic material is shock resistant polycarbonate or 25 methacrylate.

4. A device according to claim 3, characterized in that said inner layer has a thickness in the range of 2 to 3 mm.

A device according to any one of the preceding claims, characterized in that said plastic material suitably treated in order to make it opalescent is polycarbonate or methacrylate.

6. A device according to claim 5, characterized in that said outer layer of opalescent polycarbonate or methacrylate is made of a mixture stabilized in respect of ultraviolet radiation and having a thickness in the range of 35 of 70 .m.

7. A device according to claim 1, characterized in that said prismatic scores have a triangular shape.

8. A device according to any one of the preceding claims, characterized in that said scoring is longitudinal.

9. A device according to any one of claims 1 to 7, characterized in that said scoring is transversal.

10. A device according to claim 1, characterized in that said tubular structure has an inner light reflectant surface.

11. A device according to claim 10, characterized in that said tubular structure is preferably made of aluminium and/or shock resistant polycarbonate and/or metacrylate and its inner surface is made light reflectant by deposition of a polished layer of aluminium with a purity figure 2 99,95% or by means of a vacuum treatment or by means of a film of reflectant plastic material applied thereon.

12. A device according to claim 2, characterized in that said longitudinal, non-light transmissive elements are applied upon said light 15 transmissive tubular structure externally or internally or by co-extrusion. me

13. A device according to claim 2, characterized in that said longitudinal non-light transmissive portions are subjected to a mirroring treatment.

14. A device according to any one of the preceding claims, characterized in that it is modular.

15. A device according to any one of the preceding claims, characterized in that said conduit is substantially cylindrical and it is coupled at first end to a projector having a parabolic diaphram *arranged therein together with a lamp and/or it is provided, at the other end, with an optical light recuperator closure having an inner light reflectant surface with divergent parabolic optics.

16. A device according to claim 15, characterized in that said parabolic diaphram has a focus point adjustable with respect to said lamp

17. A device according to claim 16, characterized in that said parabolic diaphram has a focurs point adjustable with respect to said lamp in a range of 4*.

18. A device according to any one of claims 1-14, characterized in that a linear fluorescent lamp and a longitudinal parabolic cross-section partition are mounted in said conduit said linear lamp being arranged in the focus point of said loncitudinal parabolic partition.

19. A linear lighting device substantially as described with reference to the accompanying drawings. Dated this ninth day of January 2002 DA.MA S.R.L. Patent Attorneys for the Applicant: F B RICE CO e