Radial output light assembly

Abstract

A light assembly (10), which can be part of an inset light fixture, comprises a light source (11), a light shaping element (12) and an optical cover (13). The light shaping element (12) comprises an optical body with a light entrance surface (122) at a first end for coupling light into the optical body and a plurality of first facets (126) and a plurality of second facets (127) arranged in alternation concentrically about an optical axis (14) at a second end. An internal reflection surface (125) is circumferential to the optical body between the first end and the second end. The plurality of first facets (126) are configured to direct light from within the optical body towards the plurality of second facets (127) from which light is configured to be emitted in a plurality of first light bundles (21, 22). The optical cover (13) comprises a lens (133) concentrically about the optical axis for shaping the plurality of first light bundles (21, 22) into second light bundles (23) which are oblique and / or radial to the optical axis (14).

Description

Radial output light assemblyTechnical field

[0001] The present invention is related to light assemblies in which light is emitted radially about an optical axis. Specifically, the present invention is related to inset light fixtures, such as inset airfield lights incorporating such light assemblies.Background art

[0002] Omnidirectional inset lights for airfield ground lighting, such as inset light models Nos. SL-TE-I and SL-SG-I manufactured by ADB Safegate, Belgium, are known. In the present context, the term ‘omnidirectional’ refers to a light beam emitting in a range of vertical angels over a full 360° about a typically vertically arranged optical axis, i.e. an omnidirectional beam refers to a light beam which is fully rotationally symmetric (at any angle) about the optical axis. The luminous intensity is typically maximal over a vertical angle between 70° and 90° measured from the optical axis, while being lower at smaller angles, e.g. between 20°-70° from the optical angle. Such lights typically utilize a collimator to collimate the light and an inverted conical mirror to redirect the collimated light in the desired omnidirectional beam. One disadvantage of such lights is that the collimator and the conical mirror need to be well-aligned to obtain satisfactory omnidirectionality. Another disadvantage is that a significant elevational projection from ground level is required to achieve light output at 90° vertical angle (i.e. in horizontal direction). The SL-TE-I and SL-SG-I lights have 10 mm elevation. As a consequence, the light is prone to rupture when struck.

[0003] US 2002 / 0136027 discloses elevated airfield edge lights including a tapered rod through which light emitted by a LED is guided axially and an omnidirectional light is obtained. Light is transmitted from the small end of the tapered rod substantially parallel to the longitudinal axis of the rod and is reflected by a conical concavity depression manufactured into the large end of the tapered rod to obtain an omnidirectional beam. The light is totally internally reflected from the surface of the conical depression at the point of contact therewith resulting in the dispersion about a 360° pattern at a small angle, which angle is determined by the structure of the conical depression. One disadvantage is that the light is an elevated light and required an even higher protrusion from ground to obtain the omnidirectional beam. Moreover, US20130099665A1 discloses a light assembly comprising a light source, a light shaping element and an optical cover.Summary

[0004] It is an aim of the present disclosure to provide a light assembly providing an omnidirectional light beam and an inset light including such light assembly that overcomes the drawbacks of the prior art. It is an aim to provide such light assemblies that are more economical, require less assembling effort and / or which enable to further reduce the elevational projection of the inset light fixture.

[0005] According to a first aspect of the disclosure, there is therefore provided a light assembly, particularly an omnidirectional light assembly, as set out in the appended claims. The light assembly comprises a light source, a light shaping element, and an optical cover. The light shaping element is interposed between the light source and the optical cover along an optical axis. The light shaping element comprises an optical body, a light entrance surface at a first end of the optical body proximal to the light source for coupling light into the optical body, and a plurality of first facets and a plurality of second facets arranged in alternation concentrically about the optical axis at a second end of the optical body opposite the first end. The light shaping element further comprises an internal reflection surface circumferential to the optical body, arranged between the first end and the second end. The internal reflection surface advantageously acts as a collimator and is advantageously configured to direct light by total internal reflection to the plurality of first facets.

[0006] The plurality of first facets are configured to direct incident light from within the optical body towards the plurality of second facets, advantageously by total internal reflection. Light is configured to be emitted from the second facets in a plurality of first light bundles. The optical cover comprises a lens arranged concentrically about the optical axis and configured to shape (e.g., by refraction) the plurality of first light bundles into one or more second light bundles emitting in directions which are oblique and / or radial to the optical axis, advantageously in full rotational symmetry. The lens of the optical cover is advantageously a(n annular) prismatic lens which has full rotational symmetry about the optical axis.

[0007] As a result of the construction of omnidirectional light assemblies according to the present disclosure, the elevational projection of the optical cover above a mounting level can be reduced considerably while still allowing to obtain a horizontal or near horizontal light beam (i.e. radial relative to the optical axis). This is particularly due to the construction of the light shaping element having a collimating internal reflection surface and multiple concentric first and second facets, which act as annular concentric prismatic lenses, and allow for concentrating the light to a high extent and already shaping the light into a desired beam that only further needs to be directed to adesired angle by the optical cover. This can furthermore be obtained with components, such as the optical cover and the light shaping element which are small in size which is beneficial for service life and renders present light assemblies more robust. In addition, the light assemblies allow for an improved energy efficiency due to less components being utilized, reducing losses. The components of present light assemblies are furthermore easy to manufacture which reduces cost. In addition, the smaller number of components eases mounting and alignment, which further reduces manufacturing and installation costs. Furthermore, since present light assemblies are more compact, they can be integrated with greater ease in light fixtures advantageously also as an addition to directional lights incorporated in the light fixtures.

[0008] According to a second aspect of the disclosure, there is provided an inset light fixture as set out in the appended claims. The inset light fixture comprises the light assembly according to the first aspect and is advantageously an airfield ground light.Brief description of the drawings

[0009] Aspects of the invention will now be described in more detail with reference to the appended drawings, wherein same reference numerals illustrate same features and wherein:

[0010] Figure 1 represents a cross-sectional view of a light assembly according to the present disclosure;

[0011] Figure 2 represents a cross-sectional perspective view of a light shaping element of the light assembly of Fig. 1 ;

[0012] Figure 3 represents a diagram of the light bundles passing through the light assembly of Fig. 1 ;

[0013] Figure 4 represents a cross sectional view of an inset light fixture incorporating the light assembly of Fig. 1 as an omnidirectional light;

[0014] Figure 5 represents a cross sectional view along the section line A-A of Fig. 6 of an inset light fixture incorporating the light assembly of Fig. 1 as an omnidirectional light and additionally incorporating a pair of directional light assemblies;

[0015] Figure 6 represents a top view of the cover lid of the inset light fixture of Fig. 5.Detailed description

[0016] Referring to Fig. 1 , a light assembly 10 according to the present disclosure comprises a light source 11 , a light shaping element 12 and an optical cover 13. These three components are arranged along an optical axis 14, with the light shaping element 12 being interposed between the light source 1 1 and the optical cover 13.

[0017] The light source 11 is advantageously a light emitting diode (LED), particularly a single LED centred on the optical axis 14. Use of a single LED advantageously facilitates coupling of light emitted by the LED into the light shaping element 12. It will be appreciated that the light source can be configured to emit visible light, e.g. white light or light of a defined colour such as red, green or yellow. In addition, or alternatively the light source can be configured to emit non-visible light, such as in the infra-red (IR), near infra-red (NIR) or ultra-violet (UV) region.

[0018] The light shaping element 12, which is illustrated in greater detail inFig. 2, comprises an optical body 121. Optical body 121 extends from a first end 123 proximal to the light source 11 to a second end 124 opposite to first end 123 and proximal to the optical cover 13. A light entrance surface 122 is arranged at the first end 123 and is configured to couple light emitted by the light source 11 into the optical body 121 . The light entrance surface 122 can have any suitable shape. Advantageously, light entrance surface 122 comprises a convex surface portion 1221 concentric with the optical axis 14. Convex surface portion 1221 advantageously faces the light source 11 and can be recessed from the first end 123 of the optical body 121. The light entrance surface 122 can further comprise an upright wall 1222 extending coaxially with optical axis 14, from the first end 123 to the convex surface portion 1221 . A recess 1223 into the optical body121 is delimited by the convex surface portion 1221 at the top and by the upright wall 1222.

[0019] The light source 11 is optically coupled to the light entrance surface122 so that light emitted from the light source enters the optical body 121 through the light entrance surface. Advantageously, light from light source 11 enters through either one of convex surface portion 1221 and upright wall 1222, or both, into the optical body 121.

[0020] The light shaping element 12 further comprises an internal reflection surface 125 advantageously forming a circumferential surface of the optical body 121. Internal reflection surface 125 is coaxial with the optical axis 14 and extends between the first end 123 (light entrance surface 122) and the second end 124. Internal reflection surface is advantageously a total internal reflection surface and is configured to collimate light entering the optical body through the light entrance surface 122. In particular, the internal reflection surface 125 is configured to direct the light towards the second end 124 by total internal reflection. The internal reflection surface 125 can have any suitable shape, such as dome-shaped or shaped as an inverted cone which may be truncated by the light entrance surface 122.

[0021] The light shaping element 12 further comprises a plurality of first facets 126 and a plurality of second facets 127 arranged in alternation concentrically about the optical axis 14, at the second end 124, and preferably adjacent to the internal reflection surface 125 along the optical axis 14. The first facets 126 are configured to direct light that is incident on the first facets 126 from within the optical body 121 to the second facets 127. Light is advantageously directed by the first facets 126 by total internal reflection, towards the second facets 127. Light is emitted out of the optical body 121 through the second facets 127. The second facets 127 are hence configured as light exit surfaces through which light egresses from the light shaping element 12.

[0022] The first facets 126 and the second facets 127 advantageously form a plurality of concentric annular prismatic lenses, such as a Fresnel lens. The first and second facets can have any suitable shape. They can be shaped as tapered surfaces along the optical axis, such as linearly tapered (e.g., conical surfaces), or be tapered according to any suitable non-linear curve which may be convex or concave. The number of concentric annular first and second facets 126, 127 is not particularly limited. There are advantageously at least three, at least four or at least five concentric annular first facets and an equal number of second facets arranged at the second end 124. Each second facet advantageously is associated with a respective second facet to form an annular prismatic element. It will be appreciated that the larger the first and second facets will be in number, the smaller the projection height of the facets need be along the optical axis. The annular prismatic elements or lenses formed by the first and second facets are advantageously arranged at a same position along the optical axis 14. In some examples, the bases 128 of the annular prismatic elements are coplanar.

[0023] The first facets 126 and second facets 127 can be integral with the optical body 121 , and hence form surfaces of the optical body. This reduces component count and facilitates alignment and assembly. Alternatively, the first and second facets can be formed by separate lenses optically coupled with the optical body 121 . It will be appreciated that the optical body 121 (and the first and second facets) can be made of any suitable material, such as glass or a synthetic polymer material, such as plastics, particularly polycarbonate or poly methyl methacrylate.

[0024] It will be appreciated that light shaping element 12, particularly optical body 121 and any one of the light entrance surface 122, internal reflection surface 125 and first and second facets 126, 127 have a shape that is advantageously fully rotationally symmetrical (i.e., at any angle) about the optical axis 14.

[0025] Referring again to Fig. 1 , the optical cover 13 comprises an optical body 131 . A light entrance surface 132 of the optical body 131 is optically coupled to thesecond facets 127 so that light egressing the light shaping element 12 enters the optical cover 13 (optical body 131 ) through the light entrance surface 132. Light energy from the light shaping element can be refracted by light entrance surface 132. The optical cover 13 is advantageously configured to allow light energy to pass substantially undisturbed, e.g. with no substantial energy loss, through the optical cover 13. Specifically, light energy from the light shaping element is refracted by light entrance surface 132

[0026] The optical cover 13 further comprises a light exit surface 133 at an end of the optical body 131 opposite the light entrance surface 132. Light exit surface 133 is advantageously shaped as an annular prismatic lens concentric with the optical axis 14. Light exit surface 133 is configured to direct the egressing light into its final, omnidirectional beam. The optical cover 13 can be made of any suitable optical material, such as glass or synthetic polymer material.

[0027] Referring to Fig. 3, light emitted by the light source 11 enters the light shaping element 12 via light entrance surface 122 and is collimated, e.g. by internal reflection surface 125, onto the first facets 126. Light incident on the first facets 126, is directed, advantageously by total internal reflection, to the second facets 127 from where the light egresses the light shaping element 12. Light egresses from the second facets 127 as a plurality light bundles 21 , 22. Light bundles 21 , 22 emitted from different second facets 127 can be oblique relative to one another (i.e., non-parallel), or are advantageously parallel. Each of the light bundles 21 , 22, e.g. each light bundle egressing from each of the second facets 127, advantageously is fully rotationally symmetric at any angle about the optical axis 14. The light bundles 21 , 22 advantageously have a maximal luminous intensity at vertical (elevation) angles a between 40° and 75° measured from the optical axis 14, preferably between 45° and 70°, preferably between 50° and 65°. It will be appreciated that the vertical angle a advantageously should not be too large to avoid that the light bundles 21 , 22 bump onto the adjacent set of first and second facets 126, 127.

[0028] Light bundles 21 , 22 are directed to the optical cover 13 and enter the body of the optical cover through the light entrance surface 132. Light bundles 21 , 22 are directed through the body of the optical cover 13 towards the light exit surface 133 in advantageously full rotational symmetry about the optical axis 14. The light bundles 21 , 22 are refracted at the light exit surface 133, e.g. by the prismatic lens formed by the light exit surface 133, to egress from light exit surface 133 as a light beam 23 which is advantageously fully rotationally symmetric about the optical axis 14, i.e., as an omnidirectional beam. The light beam 23 advantageously has a maximal luminous intensity at vertical (elevation) angles p between 60° and 90° measured from the opticalaxis 14, preferably between 70° and 90°. Advantageously, the angular width y of light beam 23 is at least 15°, advantageously at least 20°, advantageously between 15° and 40°. It will be appreciated that the luminous intensity of light beam 23 at other vertical angles, e.g. between 0° and 59°, or between 20° and 59°, or between 30° and 55° from the optical axis is typically substantially lower than the luminous intensity at the vertical angles p as indicated above, e.g. not exceeding 50% of the maximal luminous intensity output within the range of vertical angles p.

[0029] One benefit of the light assembly 10 is that it easily allows to obtain light output through light beam 23 at 90° vertical angle p (i.e., in horizontal direction if the optical axis is arranged vertically). In addition, a light beam 23 with large angular width can easily be obtained with a limited elevation H of the light exit surface 133, which is advantageously 5 mm or less, such as 4 mm or less, 3 mm or less, and advantageously as small as 2 mm or less, whereas prior art omnidirectional light assemblies require an elevational projection of more than 6 mm.

[0030] Referring to Fig. 4, light assembly 10 is advantageously integrated in an inset light fixture 30, such as an airfield ground lighting (AGL) light fixture, to obtain an omnidirectional light with very low elevational projection H above ground level 31 while still allowing to generate a horizontal omnidirectional beam. The elevational projection H of the inset light fixture can be 5 mm or less, and advantageously as small as 2 mm. The inset light fixture 30 comprises a cover lid 32 and the optical cover 13 can be mounted on the cover lid 32, particularly at its centre (concentrically). The light exit surface 133 of the optical cover 13 is arranged at an exposed surface of the cover lid 32.The light shaping element 12 and light source 1 1 can be accommodated in the inset base 33 onto which cover lid 32 is mounted. Inset base 33 can further accommodate a driver 34 and other required electrical equipment for driving the light source 1 1. Driver 34 can be supplied with power via a power supply cable 35.

[0031] Referring to Figs. 5-6, due to its small dimensions and simple construction, the omnidirectional light assembly 10 can easily be combined with one or more directional light assemblies 50 in a single light fixture, specifically an inset light fixture 40. Inset light fixture 40 comprises a cover lid 42 mounted on an inset base 43. The cover lid 42 comprises the optical cover 13 of light assembly 10 at a centre portion 423 of the cover lid 42. The other components of light assembly 10, such as the light source 11 and the light shaping element 12, as well as a driver 34 for light source 11 , can be accommodated in the inset base 43.

[0032] Cover lid 42 further comprises one or more recesses 421 , 422 arranged at a periphery of the centre portion 423. Recesses 421 , 422 extend radiallyfrom the centre portion 423, and advantageously until a circumferential edge 424 of the cover lid 42. Centre portion 423 may be slightly elevated from ground level 31. This facilitates accommodating the one or more recesses 421 , 422 in the cover lid 42. Recesses 421 , 422 accommodate directional light assemblies 50. Particularly, each recess 421 , 422 comprises an optical window 52 providing an exit path for a directional light beam generated by the light source 51 accommodated within the inset base 43. The directional light beam has an optical axis 53, which is advantageously oblique relative to the advantageously vertical optical axis 14 of the omnidirectional light assembly 10. Typical angles between optical axis 53 and optical axis 14 can be between 75° and 90°, particularly between 78° and 90°, particularly between 83° and 88°. The optical window 52 may be made in any suitable manner as known in the art, e.g. made of glass or another suitable material. The light generated by the light source 51 can be conditioned by an optical assembly as known in the art, e.g. comprising lenses, collimators and the like (not shown), before it exits through the optical window 52. The optical windows are water tightly secured in through openings defined in the cover lid 42. In the example of Figs. 5-6, the optical windows 52 are arranged to direct light beams in substantially opposite directions, although other orientations are possible. The light source 51 is driven by drivers 44 accommodated in the inset base 43. The inset light fixture 40 can comprise only one directional light assembly 50, or multiple ones as desired, which may be arranged at any suitable angle about the optical axis 14. The light exit surface 133 of the optical cover 13 and each of the optical windows 52 are arranged at exposed surfaces of the cover lid 42.

[0033] The directional light assemblies 50 can be configured as runway edge lights, taxiway edge lights and the like.

[0034] Alternatively, the omnidirectional light assemblies 10 according to the present disclosure can be integrated in elevated lights, such as elevated AGL lights.

Claims

AMENDED CLAIMS received by the International Bureau on 14 August 2025 (14.08.2025)1. An inset light fixture (30, 40), comprising a light assembly (10), said light assembly (10) comprising a light source (11), a light shaping element (12) and an optical cover (13), the light shaping element (12) being interposed between the light source (11) and the optical cover (13) along an optical axis (14), the light shaping element comprising: an optical body (121), a light entrance surface (122) at a first end (123) of the optical body proximal to the light source for coupling light into the optical body, a plurality of first facets (126) and a plurality of second facets (127) arranged in alternation concentrically about the optical axis at a second end (124) of the optical body, an internal reflection surface (125) circumferential to the optical body between the first end and the second end, the light assembly (10) being characterised in that the plurality of first facets (126) are configured to direct light from within the optical body towards the plurality of second facets (127) from which light is configured to be emitted in a plurality of first light bundles (21 , 22), and in that the optical cover (13) comprises a lens (133) arranged concentrically about the optical axis and configured to shape the plurality of first light bundles (21 , 22) into one or more second light bundles (23) which are oblique and / or radial to the optical axis (14), the inset light fixture (30, 40) being characterised in that the inset light fixture (30, 40) is an airfield ground light.

2. The inset light fixture of claim 1 , wherein the internal reflection surface (125) is configured to direct incident light by total internal reflection.

3. The inset light fixture of claim 1 or 2, wherein the plurality of first facets (126) are configured to direct incident light by total internal reflection.

4. The inset light fixture of any one of the preceding claims, wherein the plurality of first facets (126) and the plurality of second facets (127) are shaped as concentric annular prismatic lenses.

5. The inset light fixture of any one of the preceding claims, wherein the one or more second light bundles (23) are configured to be fully rotationally symmetric about the optical axis (14).

126. The inset light fixture of any one of the preceding claims, wherein the plurality of first light bundles are configured to emit at first elevation angles (a) relative of the optical axis (14) and the second light bundles are configured to emit at second elevation angles (P) relative to the optical axis greater than the first elevation angles.

7. The inset light fixture of any one of the preceding claims, wherein the one or more second light bundles (23) are configured to emit at second elevation angles (P) between 60° and 90° relative to the optical axis (14).

8. The inset light fixture of any one of the preceding claims, wherein the light source (11) comprises a light emitting diode.

9. The inset light fixture of any one of the preceding claim, further comprising a housing (33, 43) configured to accommodate the light source (11) and the light shaping element (12), and a cover lid (32, 42) comprising the optical cover (13).

10. The inset light fixture of the preceding claim, wherein the optical cover (13) has an elevational protrusion (H) of 5 mm or less relative to a ground level (31).

11. The inset light fixture (40) of any one of the preceding claims, further comprising a second light assembly (50) configured to emit a directional light having no or partial rotational symmetry about the optical axis (14).

12. The inset light fixture of the preceding claim, comprising a cover lid (42), wherein the second light assembly comprises an optical window mounted in the cover lid (42) and wherein the optical cover (13) is mounted in the cover lid.

13. An inset light fixture (30, 40), comprising a first light assembly (10), said first light assembly (10) comprising a light source (11), a light shaping element (12) and an optical cover (13), the light shaping element (12) being interposed between the light source (11) and the optical cover (13) along an optical axis (14), the light shaping element comprising: an optical body (121), a light entrance surface (122) at a first end (123) of the optical body proximal to the light source for coupling light into the optical body, a plurality of first facets (126) and a plurality of second facets (127) arranged in alternation concentrically about the optical axis at a second end (124) of the optical body,13 an internal reflection surface (125) circumferential to the optical body between the first end and the second end, the first light assembly (10) being characterised in that the plurality of first facets (126) are configured to direct light from within the optical body towards the plurality of second facets (127) from which light is configured to be emitted in a plurality of first light bundles (21 , 22), and in that the optical cover (13) comprises a lens (133) arranged concentrically about the optical axis and configured to shape the plurality of first light bundles (21 , 22) into one or more second light bundles (23) which are oblique and / or radial to the optical axis (14), the inset light fixture (30, 40) being characterised in that the inset light fixture (30, 40) comprises a second light assembly (50) configured to emit a directional light having no or partial rotational symmetry about the optical axis (14), and in that that the inset light fixture (30, 40) comprises a cover lid (42), wherein the second light assembly comprises an optical window mounted in the cover lid (42) and wherein the optical cover (13) is mounted in the cover lid.

14. The inset light fixture of the preceding claim, comprising a housing (33, 43) configured to accommodate the light source (11) and the light shaping element (12), and a cover lid (32, 42) comprising the optical cover (13).

15. The inset light fixture of the preceding claim, wherein the optical cover (13) has an elevational protrusion (H) of 5 mm or less relative to a ground level (31).

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