WO2009093168A1

WO2009093168A1 - Lamp

Info

Publication number: WO2009093168A1
Application number: PCT/IB2009/050192
Authority: WO
Inventors: Cesare Alberti
Original assignee: Simlux S.P.A.
Priority date: 2008-01-22
Filing date: 2009-01-20
Publication date: 2009-07-30
Also published as: TW200940902A; ITBS20080009A1

Abstract

A lamp, specifically for outdoor illumination, comprising a lamp body (8), a light source (16), lodged in said lamp body (8), a lens (20) able to receive and diffuse the beam of light produced by the light source (16), said lens (20) being lodged in a relative seat of the lamp body (8). The lens (20) is joined directly to the lamp body (8) so as to form a closure cap of the lamp body (8) protecting the light source (16), the lens (20) being joined to the lamp body (8) by sealing and attachment means (80) entirely contained inside the lamp body (8).

Description

DESCRIPTION

"Lamp"

[001] The present invention relates to a lamp and specifically a lamp for illuminating extensive or long, indoor or outdoor areas, such as corridors.

[002] In the lighting sector, especially for outdoor use, there is the need to protect the light source from dust and especially from water and damp present in the air. [003] In fact, water and dirt can drastically reduce the life of the light source. This problem is particularly relevant in relation to LED bulbs where the life of the LED, in suitable conditions, may be up to 50 times longer than that of conventional bulbs and at least 5-10 times longer than so- called long-life bulbs. [004] To ensure the protection of the light source from water and dust, a practice known of in the art is to make lamps with a metal or plastic body, enclosed by a screen, such as glass or other transparent material, with a hermetic seal composed of a seal pressed between the body and said transparent screen.

[005] Such known solution however present various drawbacks. [006] In fact, the screen creates an air barrier in relation to the light source preventing adequate heat disposal and thus drastically reducing the duration of the light source; in the case of LEDs there is the risk of cancelling out all the benefits relative to the longer duration of such light sources compared to conventional incandescent bulbs. [007] In addition, known, state-of-the-art solutions often foresee the use of ferrules or plates attaching the screen to the lamp body by means of threaded connections: these devices increase the weight of the lamp and make assembly more complex; furthermore, such elements are subject to precocious wear and rusting if used in outdoor lamps. Lastly, such attachment devices in some cases protrude from the body of the lamp so as to interfere with the beam of light, thus limiting the lighting efficacy of the lamp.

[008] The problem which the present invention sets out to address is that of producing a lamp which overcomes the drawbacks mentioned with reference to the known technique. [009] Such drawbacks and limitations are overcome by a lamp according to claim 1.

[0010] Other embodiments of the lamp according to the invention are described in the appended claims. [0011] Further characteristics and advantages of the present invention will be evident from the description below of its preferred but not limiting embodiments, wherein: [0012] figure 1 shows a perspective view of a lamp according to one embodiment of the present invention; [0013] figure 2 shows a front view, from the side of the arrow II in figure 1, of some components of the lamp in figure 1; [0014] figure 3 shows a perspective view, in separate parts, of the lamp in figure 1 ;

[0015] figure 4 shows a cross-section view of the lamp in figure 1, along the cross-section line IV in figure 1 ; [0016] figures 5a and 5b show schematic views of beams of light respectively emitted by a plurality of lamps of the known state-of the-art and of the present invention, in illuminating rectangular areas;

[0017] figures 6a and 6b show further schematic views of beams of light respectively emitted by a plurality of lamps of the known state-of-the-art and of the present invention, in illuminating square areas.

[0018] The elements or parts of elements common to the embodiments described below will be indicated using the same reference numerals.

[0019] With reference to the aforesaid figures, reference numeral 4 globally denotes a lamp, specifically for outdoor illumination .

[0020] According to one embodiment, said lamp 4 comprises a lamp body 8, being, for example, a box shape, so as to enclose at least one inner cavity 12.

[0021] The lamp 4 comprises a light source 16, preferably an

LED (light emitting diode) , for example lodged in said cavity

12 of the lamp body 8, and a lens 20 able to receive and diffuse the beam of light produced by the light source 16. According to one possible embodiment, the inner cavity 12 is such as to accommodate solely the LED: in other words, the size of the inner cavity 12 is such as to accommodate solely the LED. [0022] The lamp 4 comprises a power supply 24 of the light source 16, able to power the source. The light source 16 is, for example, attached to a terminal board 28 which comprises electronic circuits to activate and control the source 16. [0023] According to one possible embodiment, the lamp body 8 comprises at least one plate 32, able to act as a support for the light source and/or relative terminal board 28. [0024] According to one embodiment, said plate 32 acts as a heat dissipator able to encourage the transmission of heat from the light source 16 outwards, preventing, as far as possible, overheating of the light source 16 and of the control electronics of the lamp 4.

[0025] Preferably, the plate 32 comprises at least one aperture 36 able to permit the passage of light emitted by the light source 16. [0026] According to one embodiment, the lens 20 is lodged in a relative seat 40 of the lamp body 8.

[0027] For example, the lamp body 8 comprises a pair of walls 44 defining the seat 40. According to one embodiment said walls 44 join the plate 32, for example at the aperture 36. [0028] Advantageously, the lens has a mainly longitudinal extension (X-X), the lens 20 having an essentially parabolic cross-section in relation to a cross-section plane perpendicular to said mainly longitudinal extension X-X, so that the lens 20 acquires an overall, bar-shaped configuration with a parabolic cross-section.

[0029] Preferably, the cross-section of the lens 20 is constant along the mainly longitudinal extension X-X of the lens 20. [0030] In other words, the lens 20 is essentially a straight cylinder having a parabolic cross-section in relation to a cross-section plane perpendicular to the main direction of extension X-X, the generators of the cylinder being parallel to said main extension. [0031] Such shape means that the direction of the light emitted by the light source 16 is not modified in the direction X-X, but only in a transversal direction Y-Y so that the natural cone-shaped emission is flattened in a single direction, acquiring an elliptical, almost rectangular shape. The transversal direction Y-Y is perpendicular to the direction X-X as well as to a vertical direction of emission of the beam of light. According to a further embodiment, the cross-section of the lens 20 may be variable in its longitudinal extension X-X, so that the distribution of light, in this longitudinal extension X-X, may be modified, preferably concentrating more light towards the extremity of the lamp body 8 opposite the same longitudinal extension X-X. This way the opposite effect to that of the transversal direction Y-Y is obtained; in other words the natural cone of light emitted by the LED is reduced or narrowed in the transversal direction Y-Y and increased or lengthened in the longitudinal extension X-X; this way the elliptical/rectangular shape of the cone of light emitted is further increased. [0032] According to one possible embodiment, said section presents a wall 48, flat or concave, directly facing the light source 16, to which a pair of lateral walls 52 are joined, having a parabolic profile in relation to a cross- section plane perpendicular to the mainly longitudinal extension X-X. [0033] Advantageously, the seat 40 of the lamp body 8 comprises at least one pair of walls 44 counter-shaped to the lateral walls 52 of the lens 20 so as to accommodate the lens coming into direct contact with the lens 20. [0034] Preferably, the walls 44 extend all along the extension of the lateral walls 52 of the lens 20, so as to increase the contact surface between the wall and the lens itself as far as possible.

[0035] Preferably, the walls 44 are made in metal material, so as to encourage heat exchange on contact, that is by conduction, between the lens 20 and the lamp body 8, so as to keep the entire system as isothermal as possible. Advantageously, the part of light which, even if minimal, comes out of the lens 20 laterally, can be recovered and reflected outwards and in the same direction. Furthermore, the difference in dilation caused by heat, of the lens 20 and the lamp body 8, can be reduced to a minimum thus reducing thermal and mechanical stress and lengthening the life of the lens itself 20. In fact, the lens 20 is generally made from a fragile material and if subjected to excessive thermal and mechanical stress, micro-fractures destined to shorten its life may be generated. Furthermore, accurate positioning and coupling of the lens and the light source 16, such as the LED can be ensured and maintained. [0036] Advantageously, the lens 20 is joined to the lamp body 8 so as to form a cover cap, protecting the light source 16. [0037] According to one embodiment, one emission wall 64 of the lens 20, opposite the light source 16, is positioned directly flush with a profile or external perimeter of the lamp body 8, so as to form a cover cap enclosing the lamp body 8 itself.

[0038] In other words, a wall of the lamp body 8 has a seat 40 which is closed directly by the lens without requiring the use of further screens or cover caps of the lens 20. According to a further embodiment, the lamp body 8 extends beyond the edge of the lens, entirely or with its appendages (not shown) , so that the lens 20 finds itself set inside the lamp body 8 itself. This makes it possible to mask the light source 16 to the eyes of the user, thereby achieving a reduction of light pollution (a characteristic known of in the world of lighting as cut-off) .

[0039] Advantageously, the lens 20 is attached to the lamp body by a hermetically sealed attachment 80.

[0040] According to one embodiment, the hermetically sealed attachment 80 comprises at last one seal 84 positioned between a wall 44 of the seat 40 and a lateral wall 52 of the lens 20, said seal 84 being at least partially lodged both in the lateral wall 52 and in the wall 44.

[0041] According to one embodiment, the wall 44 comprises a first groove 88, for example longitudinal, able to lodge said seal 84 at least partially.

[0042] Advantageously, the lateral wall 52 of the lens 20 comprises at least one second groove 92 able to lodge at least partially said seal 84. [0043] In one assembly configuration of the lens in its seat 40, the first and second grooves 88,92 face each other and are aligned with each other so as to accommodate the seals 84.

[0044] The seals 84 therefore constitute a restraint to the extraction of the lens 20 from the seat 40, as well as ensuring the hermetic sealing of the seat from dust and from water. The grooves 88,92 of the lens 20 and of the walls are at least partially counter-shaped 44 to the connectable seals 84.

[0045] Advantageously, the sealed attachment means are lodged entirely inside the lamp body 8, so as not to be accessible and/or visible from outside the lamp body 8, in an assembly configuration of the lamp 4.

[0046] For example, the sealed attachment means 80 comprise a pair of bars in polymer material, preferably transparent, positioned essentially parallel to said main direction of extension X-X. Preferably, the sealed attachment means 80 comprise bars with a circular cross-section.

[0047] According to a preferred embodiment, the lamp 4 comprises a pair of end plugs 100, positioned to cover the longitudinal extremities 104 of the lens 20; the main function of such end plugs 100 is to complete the hermetic seal of the lens 20. According to a further embodiment, the end plugs 100 may have a protruding rim to further ensure that the lens 20 remains in its seat. The overall system of attachment of the lens 20 is however totally free of screws which would block the lens to the lamp body in a rigid manner with the ensuing risk of causing micro fractures destined to shorten its life. [0048] The method of assembling a lamp according to the invention will now be described. [0049] Specifically, after fitting the power supply and the light source inside the lamp body, the lens is then mounted. [0050] According to a first assembly method, the seals are inserted in the seats or grooves of the lamp body, and subsequently the lens is inserted under pressure into its relative seat. The parabolic, essentially conical shape of the lens, on the side of the associable light source, favours the insertion of the lens in its seat under pressure. After reaching the limit position, the seal is partially lodged in the grooves of the lens and thus remains fixed in position.

[0051] According to a further possible assembly method, after inserting the seals in the seats of the lamp body the said seals are then tugged in an essentially longitudinal direction so as to provoke an elastic deformation causing the lengthening and consequent reduction of cross-section. The lens is then inserted in the seat and, when traction of the seals is ceased these return elastically to their original shape, thereby blocking themselves inside the seats of the lens . [0052] As may be seen from the description, the lamp according to the invention makes it possible to overcome the problems present in the known technique.

[0053] In fact, the lamp according to the present invention also permits an improvement of heat dissipation of the light and thus a longer duration of the same. [0054] In fact, the lens is positioned directly in contact with the relative seat of the lamp body, so as to ensure thermal conductivity by contact at least on the lateral surface of the lens itself. This way a heat dissipation flow is generated from the side opposite the light source and overheating phenomena of the light source are avoided, increasing the relative duration.

[0055] Furthermore, the attachment system of the lens to the lamp avoids the use of ferrules or lock bushing which, as well as increasing the weight and complexity of assembly of the lamp, tend to interfere with the beam of light emitted, reducing the luminous efficiency of the lamp.

[0056] Furthermore, in the lamp according to the present invention the use of screens to hermetically protect and cover the light source is avoided: in fact the lens itself is used as a protective screen.

[0057] This way the use of additional screens in glass or transparent material is avoided. These screens, as well as constituting in themselves a thermal insulation element, create a barrier of air between the screen and the lens which further reduces heat disposal.

[0058] As a result the light according to the present invention, thanks to the elimination of additional protective screens, is lighter and cheaper to assemble and the light source has a longer duration given that heat dissipation is considerably improved.

[0059] The use of seals as the means of hermetically sealing and attaching the lens facilitates the assembly operations of the lamp which does not require the use of ferrules or attachment plates complicating the assembly of the lamp and increasing its weight.

[0060] Furthermore, the use of threaded, metallic connections subject to deterioration, especially in the case of lamps used for outdoor illumination and therefore subject to atmospheric agents, is avoided.

[0061] Furthermore, the lamp which the present invention relates to makes it possible to emit a beam of an essentially rectangular shape so as to prevent dispersion of the beam of light outside the area to be illuminated. [0062] As shown in figures 5a, 5b, 6a, 6b, the use of a rectangular luminous beam makes it possible to:

[0063] illuminate a rectangular or square area considerably reducing the dispersion of light compared to a conventional lamp emitting a circular beam. [0064] For example, in the case of a rectangular area, such as, for example, a road, the use of two circular luminous beams (fig.5a) generates extensive areas of shadow, as well as an unnecessary dispersion of light at the edges of the rectangular area. [0065] Vice versa, the use of two rectangular beams of light according to the present invention (figure 5b) permits uniform and homogeneous illumination of the rectangular area and a practically negligible dispersion of light. [0066] Furthermore, in the case of a square area, the use of four circular beams of light (fig.6a) generates extensive areas of overlap of the beams of light making the illumination of the square area uneven, patchy and unnecessarily increasing the dispersion of light at the edges of the square area. [0067] Vice versa, the use of four rectangular beams of light according to the present invention (figure 6b) permits uniform and homogeneous illumination of the square area, without any overlap of beams of light and a practically negligible dispersion of light outside the area being illuminated.

[0068] In other words, comparing the functioning of conventional lamps (figures 5a, 6a) with lights according to the present invention (figures 5b, 6b) in lighting the same area, it may be deduced how the lamps according to the present invention produce more efficient and uniform illumination. In fact, the rectangular beams of light make it possible to prevent dispersion of the beam of light into areas outside the area to be illuminated and, by limiting the overlapping of beams coming from adjacent lights, make it possible to create areas of uniform illumination of the same intensity. In fact, the overlapping of two beams of light leads inevitably to areas which are more brightly lit, making the illumination uneven and unnecessarily increasing energy consumption, reducing the efficiency of the lamps. [0069] A person skilled in the art may make numerous modifications and variations to the lamps described above so as to satisfy contingent and specific requirements, while remaining within the scope of protection of the invention as defined by the appended claims.

Claims

1 . Lamp ( 4 ) compri s ing

- a lamp body ( 8 )

- a light source (16), lodged in said lamp body (8), - a lens (20) able to receive and diffuse the beam of light produced by the light source (16), said lens (20) being lodged in a relative seat (40) of the lamp body (8),

- a power supply (24) of the light source (16), characterised by the fact that said lens (20) is joined directly to the lamp body (8) so as to form a cover of the lamp body (8) protecting the light source (16), the lens (20) being attached to the lamp body (8) using sealing and attachment means (80) contained entirely inside the lamp body (8) so as not to be accessible and/or visible from the outside of the lamp body (8), in a configuration assembly of the lamp (4) .

2. Lamp (4) according to claim 1, wherein one emission wall (64) of the lens (20), opposite the light source (16), is positioned flush with an external profile of the lamp body (8), so as to form a closure cap of the lamp body itself.

3. Lamp (4) according to claim 1 or 2, wherein said sealing and attachment means (80) comprise at least one seal (84) positioned between a wall (44) of the seat (40) and at least one lateral wall (52) of the lens (20), said seal (84) being at least partially lodged in the wall (44) and in the lateral wall (52) .

4. Lamp (4) according to claim 3, wherein said wall (44) comprises a first groove (88) able to lodge said seal (84) at least partially.

5. Lamp (4) according to claim 3 or 4, wherein said lateral wall (52) of the lens (20) comprises at least a second groove (92) able to lodge said seal (84) at least partially.

6. Lamp (4) according to any of the previous claims, wherein said seal and attachment means (80) comprise a pair of bars in polymer material, positioned essentially parallel to said main direction of extension (X-X) .

7. Lamp (4) according to any of the previous claims, wherein said seal and attachment means (80) comprise bars with a circular cross-section.

8. Lamp (4) according to any of the previous claims, wherein said light source (16) comprises at least one LED.

9. Lamp (4) according to any of the previous claims, wherein the lens (20) has a mainly longitudinal extension (X- X) , the lens (20) having an essentially parabolic cross- section in relation to a cross-section plane perpendicular to said mainly longitudinal extension (X-X) , so that the lens acquires an overall bar shape configuration.

10. Lamp (4) according to claim 9, wherein said cross- section is constant along the mainly longitudinal cross- section (X-X) of the lens (20) .

11. Lamp (4) according to claim 9 or 10, wherein said lens (20) has a wall (48), flat or convex, directly facing the light source (16), to which a pair of lateral walls (52), are joined having a parabolic profile in relation to a cross- section plane perpendicular to the mainly longitudinal cross- section (X-X) .

12. Lamp (4) according to any of the previous claims, wherein said seat (40) of the lamp body (8) comprises at least one pair of walls (44) counter-shaped to the lateral walls (52) of the lens (20) so as to hold the lens (20) coming into contact with the same.

13. Lamp (4) according to claim 12, wherein said walls extend all along the extension of the lateral walls (52) of the lens (20) so as to increase the contact surface with the lens (20) .

14. Lamp (4) according to claim 12 or 13, wherein said walls (44) are made in metal material, so as to encourage heat exchange between the lens (20) and the lamp body (8) .

15. Lamp (4) according to any of the previous claims, wherein said light source (16) is joined to a plate (32) which comprises control circuits of the source itself.

16. Lamp (4) according to any of the previous claims, wherein said lamp body (8) comprises at least one plate (32) which acts as a heat dissipator able to encourage the transmission of heat from the light source (16) outwards, preventing overheating of the light source (16) and of the control electronics of the lamp (4) .