GB2584013A

GB2584013A - Pathway lighting bollard

Info

Publication number: GB2584013A
Application number: GB2005478.9A
Authority: GB
Inventors: Parrott Neil
Original assignee: DW Windsor Ltd
Current assignee: DW Windsor Ltd
Priority date: 2019-04-15
Filing date: 2020-04-15
Publication date: 2020-11-18
Anticipated expiration: 2040-04-15
Also published as: GB201905317D0; GB202005478D0; GB2584013B

Abstract

A bollard for pathway lighting comprises a light chamber 51 within which light is operatively generated, and a light window 50 is defined through which the generated light is cast forward. A diffuser pane 35 is positioned across a first portion of the light window 50. A relatively low-intensity and diffuse lateral beam is emitted through the diffuser pane 35. A relatively high-intensity and non-diffuse beam is emitted downwardly through a second portion of the light window 50 uninterrupted by the diffuser pane 35.

Description

Pathway lighting bollard

Field of the invention

The present invention relates to a lighting device. In particular, the present invention relates to an outdoor pathway lighting bollard for casting a path beam for illuminating a pathway adjacent to the bollard.

Background to the invention

Relatively low-level outdoor lighting bollards are known in the art. When installed, such lighting bollards are generally less than 1.5 metres tall, and more usually between 0.4 and 1 metre tall -and so less than the height of almost all adults. Compared to tall, overhead lighting units such as street lights, they represent an economical way to illuminate outdoor sites such as pathways; a smaller quantity of material is needed to manufacture bollards, and their installation is significantly less physically demanding than overhead lighting. The illuminating part of such bollards is ideally situated near to the top of them to maximise the extent of a pathway that can be illuminated. However, lighting direction and intensity is often poorly-controlled leading to various problems.

For example, many bollards have omnidirectional lighting components. This is energy inefficient when such bollards are positioned adjacent to a pathway; light that is cast away from the pathway is wasted.

Also, if a powerful light source is used to illuminate a greater extent of the pathway, then this can subject the users of the pathway to glare if that light is not properly handled.

Additionally, light rising into the sky from the bollard is also wasteful and contributes to light pollution.

Light-directing structures such as baffles can be used to control this problem. However, these are wasteful of light output and thus the energy used to power the lighting bollard.

Also, the complexity of arrangement of such additional structures can add cost, and detract from the ease with which a lighting device can be manufactured and subsequently maintained.

Whilst a strong direct light within the line of sight of users of the pathway is undesirable, it is nonetheless useful to provide at least low-intensity light in a region above the pathway. This is so that users of the pathway can recognise one another's facial features. One way of doing this is to use a greater number of lower-intensity lights along the length of a pathway, but this can be uneconomical.

It is against this background that the present invention has been conceived.

Summary of the invention

According to a first aspect of the present invention there is provided a lighting device such as a pathway lighting bollard. The device may comprise a head. The head may be elevated.

The head may comprise a light chamber. Light may be operatively generated within the light chamber. The head may define a light window. The generated light may be cast forward through the light window. Accordingly, the generated light may be cast forward of the device in use.

Preferably, the head comprises a diffuser pane. The diffuser pane may be positioned across a first portion of the light window. A lateral beam may be emitted through the diffuser pane.

A path beam may be emitted through a second portion of the light window uninterrupted by the diffuser pane. Ideally, the lateral beam is relatively low-intensity and/or diffuse compared with the path beam. Ideally, the path beam is for illuminating a pathway forward and below the head of the device, and so may be emitted downwardly through the second portion of the light window. The head may be configured so that light escapes from the light chamber only via the light window.

Preferably, the first portion of the light window that is interrupted by the diffuser pane is situated above the second portion of the light window. The top of the light window may be approximately level with the top of the bollard. The device, when installed, may have a height of less than 1.5 metres. More preferably, the device has a height of between 0.4 and 1 metres.

The light chamber may define a first volume situated rearward of the diffuser pane. The light chamber may define a second volume situated rearward of the second portion of the light window. Ideally, the second volume is contiguous with the first volume along a boundary, and the boundary is ideally level with a bottom edge of the diffuser pane.

Preferably, the head comprises a diffusing reflector that is situated, at least in part, within the second volume of the light chamber. The diffusing reflector may be positioned and arranged to reflect and diffuse light passing into the second volume of the light chamber from the first volume of the light chamber. The diffusing reflector may be positioned and arranged so that substantially all of the light that is externally visible through the second portion of the light window is light that the diffusing reflector has reflected and diffused. Ideally, this is from a position outside of the path beam, and in particular a position above a horizontal plane level with a bottom edge of the diffuser pane. Ideally, the light that the diffusing reflector has diffused and reflected out through the second portion of the light window exhibits substantially uniform light intensity. Additionally, the light that the diffusing reflector has diffused and reflected out through the second portion of the light window may represent a secondary component of the lateral beam. The head may be configured to define an uninterrupted light void below the boundary and between the second portion of the light window and the diffusing reflector.

The diffusing reflector may be constructed from a single integrally-moulded piece of material, such as an optical grade polycarbonate. The material may have a reflectivity of greater than 95%. More preferably, the material has a reflectivity of greater than 98%.

Preferably, the device comprises a lateral beam light module having at least one lateral beam light source for generating the lateral beam. Preferably, the device comprises a path beam module having a path beam light source for generating the path beam. Preferably, the light chamber houses the lateral beam light module and/or the path beam light module, and/or their respective light sources.

The first volume of the light chamber may accommodate the path beam light module and the lateral beam light module, or components thereof. In other words the lateral and path beam light modules and/or their light sources may be positioned within the first volume, above the boundary between the first and second volumes of the light chamber. In particular, the path beam light source may be situated at or near the boundary between the first and second volumes of the light chamber. Preferably, the path beam light source is situated closer to a midpoint than an edge of the boundary between the first and second volume of the light chamber.

The path beam light module and/or the path beam light source may be oriented transverse to the lateral beam light module and/or the lateral beam light source. The path beam light source may be positioned and oriented to face away from the first volume and towards the second volume of the light chamber. Thus the path beam light source may be configured to direct substantially all the light that it generates into the second volume of the light chamber. Preferably, the path beam light module comprises a light guide for guiding most of the light that it and/or the path beam light source generates through the second volume and towards the second portion of the light window.

Preferably, the lateral beam light module is configured and positioned relative to the diffuser pane so that an outwardly-facing surface of the diffuser pane exhibits substantially uniform light intensity distribution. Preferably, the at least one lateral beam source is positioned substantially toward the rear of the first volume of the light chamber. The lateral beam light module may comprise at least one lateral beam light source that emits light according to a substantially regular radiation pattern that is rotationally symmetrical about its optical axis. The at least one lateral beam light source may be in the form of an LED package.

The lateral beam light module may comprise a set of lateral beam light sources that are positioned and oriented relative to the diffuser pane so that their respective optical axes intersect with the diffuser pane at regular intervals. Preferably, each lateral beam light source is spaced from the diffuser pane at a distance substantially the same as another lateral beam light source of the set. Preferably, the set of lateral beam light sources are spaced at regular intervals to one another, and oriented with their respective optical axes being substantially parallel to one another.

Preferably, the set of lateral beam light sources are distributed across a first planar support, and the path beam light source is held on a second planar support extending perpendicular to the first planar support.

Preferably, the second support, on which the path beam light source is held, extends in a horizontal plane over an area smaller than that of the interior of the light chamber that accommodates it, thereby allowing light travelling within the light chamber transverse to that horizontal plane to bypass the support.

Preferably, the diffuser pane is substantially flat along a vertical plane, and the set of lateral beam light sources are distributed across a planar support oriented substantially parallel to that vertical plane.

Preferably, the head comprises an external lens that forms a seal across the light window between an exterior and interior of the head of the bollard.

Preferably, the external lens comprises a relatively smooth exterior surface, and an inner surface comprising refracting structures shaped to spread light passing through the light window via the external lens.

Preferably, the bollard comprises a stem, the head surmounting the stem. Preferably, the bollard comprises a root for countersinking into ground to secure the bollard. Preferably, the stem surmounts the root. Preferably, the head is configured to physically and electrically decouple from the stem.

Preferably, the path beam is confined within a narrower volume than that of the lateral beam.

Preferably, an envelope of the path beam is confined by a perimeter defined by the second portion of the light window.

Preferably, the maximum luminous intensity of light cast by the bollard is predominantly generated by the path beam.

Preferably, as measured in a vertical plane extending forward of the bollard, the device, in operation, emits light at its maximum luminous intensity at an angle between 90 degrees and 20 degrees, wherein 180 degrees corresponds to an axially upward direction towards the sky, and 90 degrees corresponds to a direction parallel to the ground, and away from the front of the device. Ideally, this vertical plane extends perpendicularly to a planar light window.

Within said vertical measurement plane, the device, in operation, may emits light at: * its maximum luminous intensity at an angle of between 40 and 80 degrees, preferably between 50 and 70 degrees, and more preferably between 55 and 65 degrees; * less than 50% of its maximum luminous intensity at an angle between 150 and 100 degrees, preferably between 140 and 90 degrees; * less than 25% of its maximum luminous intensity at an angle less than 20 degrees or greater than 150 degrees; and/or * less than 5% of its maximum luminous intensity at any angle less than 0 degrees or greater than 180 degrees.

Preferably, the lateral beam produces less than 50% of the maximum luminous intensity of light cast by the device.

According to a second aspect of the present invention there is provided a lighting assembly for a pathway lighting bollard. The lighting assembly may comprise a light chamber within which light is operatively generated. The lighting assembly may define a light window through which said generated light is cast forward of the lighting assembly in use, the lighting assembly further comprising a diffuser pane that is positioned across a first portion of the light window and through which a relatively low-intensity and diffuse lateral beam is emitted, wherein a relatively high-intensity and non-diffuse path beam is emitted downwardly through a second portion of the light window uninterrupted by the diffuser pane.

It will be understood that features recited herein to be preferable are not necessarily essential to one or more aspects of the present invention. Additionally, features and advantages of different aspects of the present invention may be combined or substituted with one another where context allows.

For example, the features of the bollard described in relation to the first aspect of the present invention may be provided as part of the lighting assembly described in relation to the second aspect of the present invention. For example, the lighting assembly may comprise features such as the path beam light module and the lateral beam light module.

Furthermore, such features may themselves constitute further aspects of the present invention. For example, the features of the bollard, such as the head, stem and/or root may themselves constitute further aspects of the present invention.

Brief description of the drawings

In order for the invention to be more readily understood, embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is an overhead perspective schematic view of a lighting bollard according to a first embodiment of the present invention, the lighting bollard positioned adjacent to a pathway; Figure 2 is an enlarged view of a root of the bollard of Figure 1; Figures 3 and 4 are perspective exploded views of a head of the bollard of Figure 1, the head being shown in isolation; Figure 5 is a front view of the head of the bollard of Figure 1, the head being shown in isolation; Figure 6 is a sectional view of the head of the bollard of Figure 5 taken along line A-A; Figure 7 is an enlarged sectional schematic side view of part of the head of the bollard of Figure 6; Figure 8 is sectional schematic side view of the bollard and adjacent pathway of Figure 1; Figure 9 is an isolux diagram representing the light distribution of the lighting bollard of Figure 1 over a horizontal planar surface level with the pathway shown in Figure 1; and Figure 10 is a photometric polar chart illustrating light distribution of the lighting bollard of Figure 1.

Specific description of the preferred embodiments

Figure 1 is an overhead perspective schematic view of a lighting bollard 1 according to a first embodiment of the present invention. The lighting bollard 1 is generally elongate along a longitudinal axis X, and is shown in Figure 1 in position adjacent to a level pathway 2 that generally extends along a horizontal plane.

From top to bottom, the bollard 1 comprises an elevated head 30 that surmounts a stem 20 and a root 10. The head 30 forms, at least in part, a lighting assembly which causes light to be cast by the bollard 1 in operation onto the pathway 2 as will be described further below.

When the bollard 1 is installed alongside the pathway 2, the root 10 is countersunk into a region of ground next to the pathway 2 such that the bollard is upstanding, with its longitudinal axis X extending perpendicularly relative to the planar surface formed by the pathway 2. The stem 20 and head 30 rise vertically, with the overall height of the bollard being approximately 1 metre from the pathway 2.

The bollard 1 has an outer perimeter that has rounded edges, but otherwise generally conforms to the shape of an isosceles trapezoid in horizontal section, the trapezoid having a first set of internal angles, each of approximately 95 degrees, and a second set of internal angles, each of approximately 85 degrees. The small difference between the first and second set of internal angles means that the outer perimeter is almost rectangular in shape.

The two parallel lines forming the isosceles trapezoid correspond to a front and a rear of the bollard, with the front of the bollard being slightly wider than the rear. The other two non-parallel lines of the trapezoid are of equal length, and correspond to left and right sides of the bollard.

In general, the outer perimeter of the bollard is substantially constant along the vast majority of its longitudinal length. Accordingly, the bollard 1 generally defines four main vertically-extending planar outer surfaces: a front surface 21, a left surface 22, a right surface 23 and a rear surface 24. The bollard 1, at the head 30, also has a top surface 25 that slopes downward from front to back at an angle of approximately 5 degrees relative to the horizontal. Advantageously, this prevents rainwater pooling on top of the bollard, which is guided towards the rear surface 24 of the bollard 1.

In the present embodiment, the root 10 and stem 20 of the bollard 1 are integral with one another. However, in alternatives, the root 10 and stem 20 may be independent components that are connected together. In further alternatives, the stem 20 may simply be provided with a lower flange via which the bollard may be affixed to a suitable supporting surface. For example, the bollard can be bolted through the lower flange to the pathway itself.

Alternatively, the flange may be bolted and buried below the level of the pathway 2.

The root 10 and stem 20 of the present embodiment are primarily distinguished from one another by their position below or above ground respectively when the bollard 1 is installed in position. However, to aid correct installation, with countersinking of the root 10 to the correct depth, a mark 26 is provided on the bollard to indicate the border between the root 10 and the stem 20.

Referring to Figure 2, which is an enlarged view of the root 10 of the bollard 1, the root 10 comprises an anchor 11 which resists uprooting of the bollard 1 once it has been installed.

Furthermore, the anchor 11 resists twisting of the bollard 1 about the longitudinal axis X, and so the bollard can be maintained in the correct orientation relative to the pathway 2, with the front surface 21 of the bollard 1 facing across the width of the pathway 2. The outer perimeter of the bollard 1 is not rotationally symmetrical and so this also further resists twisting. Furthermore, the planar front surface 21 of the bollard 1 makes it easier for an installer to correctly estimate how to position and aim the bollard 1 relative to a pathway 2 during installation.

The root 10 and stem 20 have a predominantly tubular construction with walls of regular thickness. Accordingly, the horizontal cross-sectional profile of the root 10 and stem 20 is primarily defined by the outer perimeter and a slightly smaller inner perimeter, each having the same shape corresponding to that of a isosceles trapezoid as described above.

This defines a hollow interior within which the electrical components of the bollard 1 can be housed. Notably, an electrical cable 12 is fed into the bollard through an opening 13 in the root 10 and is led within the interior of the bollard from the root 10 via the stem 20 towards the head 30. In alternatives, the opening 13 need not be provided, and the electric cable 12 can simply be fed into the bollard via the open underside of the root 10.

Referring back to Figure 1, the head 30 of the bollard 1 is not formed integrally with the stem 20, but rather is an independent component of the bollard 1 that can be retrofitted to the stem 20 once the stem 20 and root 10 have been installed into position. Installation may involve rough handling -for example, subjecting the top of the bollard to impact to drive the root 10 into the ground. Thus, initially separating the head 30 from the stem 20 prevents damage to the relative fragile head 30 during installation.

Moreover, the head 30 can be decoupled from the stem 20 and replaced with another head. This is useful for facilitating quick repair of the bollard 1 in the event that the constituents of the head 30 are subject to damage or electrical failure. To further facilitate this, the head 30 comprises an electrical connector permitting electrical coupling and decoupling with the electrical cable 11.

In general, the head 30 comprises a body portion 31 and a plug portion 32. Only the body portion 31 is visible in Figure 1; the axially-lower plug portion 32 of the head 30 is telescopically slotted into an axially-upper socket portion 27 of the stem 20, with the plug portion 32 locating within the hollow interior of the stem 20. The plug portion 32 of the head 30 and the socket portion of the stem 20 thus define coupling interfaces via which the head 30 and stem 20 are reversibly connectable with one another physically.

Figures 3 and 4 are perspective exploded views of a head 30 in isolation. The plug portion 32 is integrally-formed with the body portion 31 which surmounts the plug portion 32 at an axially-upper region of the head 30. The body portion 31 has an outer perimeter in horizontal cross-section that matches that of the stem 20 such that when the head 30 is fitted to the stem 20, the entire assembled bollard 1 assumes the shape of a post of uniform horizontal cross-section. As well as being aesthetically appealing, this makes the bollard less likely to accumulate dirt and water, and so improves its reliability and makes it easier to clean.

The plug portion 32 has a similar shape, but a smaller outer perimeter than the body portion 3110 enable the head 30 to be slotted into the stem 20. Moreover, the plug portion 32 narrows towards its axially-lower end to facilitate its insertion into the socket portion 27 of the stem 20, with the axially-upper end of the plug portion 32 having an outer perimeter conforming with an inner perimeter of the axially-upper socket portion of the stem 20 to form a clearance fit with it.

Referring to Figure 5, which is a front view of the head 30 of the bollard 1 shown in isolation, whilst the plug portion 32 and the body portion 31 are integrally formed, the transition between them is defined by a stepped formation 33. This bears upon a complementarily-shaped upper end of the socket portion of the stem 20. The stepped formation and upper end of the stem 20 each have trapezoidal shape matching the horizontal cross-sectional profile of the walls of the stem 20. A correspondingly-shaped resilient seal can also be provided between the stepped formation 33 and the upper end of the stem 20 to resist ingress of water.

The head 30 houses the components of the lighting assembly of the bollard 1. These are configured and arranged as will be described to cast light forward from the bollard 1, with a relatively high intensity path beam being cast forward and downward to illuminate the pathway 2, and a relatively low-intensity lateral beam being cast across a region across and above the pathway 2.

Referring also to Figure 6 which is a sectional view of the head 30 of the bollard of Figure 5 taken along line A-A, the body portion 31 comprises a front wall 41, a left wall 42, a right wall 43, and a rear wall 44, the exterior of which respectively form an upper part of the front surface 21, left surface 22, right surface 23 and rear surface 24 of the bollard in general The body portion 31 also comprises a top wall 45 the exterior of which forms the sloping top surface 25 of the bollard 1.

The front, left, right and top walls 41, 42, 43, 45 of the body portion 30 are positioned and arranged to define a frame around a light window 50 located at the very top and front of the bollard 1. Moreover, the frame is primarily defined by front ends of the top, left and right walls 45, 42, 43, and an upper edge of the front wall 41. Accordingly, the light passing through the light window 50 is emitted from the axially-uppermost region of the bollard 1, maximising the vertical height of the source of illumination whilst minimising the quantity of material required to elevate it.

The frame of the light window 50 defines an entrance into a cuboidal light chamber 51 within which various components of the lighting assembly are housed. The light chamber flares gently outwards such that the entrance defined by the frame of the light window 50 is both wider and taller than the interior surface of the rear wall 44 behind it. The frame is contoured to define a pair of peripheral recesses 53, 54 which lead into the light chamber 51 in a stepwise fashion. A floor 46 of the light chamber 51 spans between the rear wall 44 and a lower end of the frame of the light window 50. The floor 46 is interrupted by a through-hole 47 located toward the rear part of the floor 46, and through which wires (not shown) are routed between the light chamber 51 situated at an upper region of the head 30, and a lower chamber 52 of the head 30.

The lower chamber 52 extends into a lower region of the body portion 31, and moreover extends the entire vertical height of the plug portion 32 so that the plug portion 32 defines an opening at its lower end. The lower chamber accommodates an LED driver 55 and an electrical connector 56 that permits electrical coupling and decoupling of the LED driver with the electrical cable 12. Relatively high voltage (120-240V) electrical power supplied via the electrical cable 12 is transformed by the LED driver 55 to relatively low voltage (=<12V) suitable for powering LEDs that are responsible for generating the path and lateral beams.

This is supplied by wires (not shown) which lead from the LED driver 55 through the through-hole 47 and into the upper light chamber 51.

Referring back to Figures 3 and 4, the head 30 comprises an external lens 34, a translucent diffuser pane 35, a diffusing reflector 36, a lateral beam light module 60 and a path beam light module 70. The external lens 34 and translucent diffuser pane 35 locate within a respective one of the pair of peripheral recesses 53, 54, with the external lens 34 forward of the diffuser pane 35. The external lens 34 is relatively transparent and non-diffuse compared with the diffuser pane 35. It should be noted that the external lens 34 and translucent diffuser pane 35 are omitted from Figures 4 and 5.

With continued reference to Figures 3 to 6, the lateral beam light module 60 comprises a first planar support 61 formed in part by a first printed circuit board (PCB) 61, a first pair of wire connectors 62, and a set of lateral beam light sources in the form of surface-mounted LED packages 63. The surface-mounted LED packages 63 are mounted on the first PCB 61, positioned and arranged in a regular 4x5 matrix.

Each surface-mounted LED package 63 emits light according to a substantially regular radiation pattern that is rotationally symmetrical about an optical axis that extends perpendicularly relative to a plane of the first PCB 61 on which each LED package 63 is mounted. Each LED package 63 has a luminous flux of approximately 30 lumens, with the maximum intensity point peaking at 0 degrees (i.e. along the optical axis). Additionally, the full angular width of the radiation pattern at the half maximum intensity point (also referred to as the beam angle) is approximately 110-120 degrees. An LED package that is suitable for use as a lateral beam light source 63 with the present embodiment is manufactured by Nichia®, for example type NFSL757GT.

These LED packages 63 are electrically connected via the PCB 61 to the first pair of wire connectors 62. The PCB 61 also defines screw holes through it, allowing the lateral beam light module 60 to be secured into position by screws 66 on to the rear wall 44 of the body portion 31.

The path beam light module 70 comprises a second planar support formed in part by a second PCB 71, a second pair of wire connectors 72 and a path beam light source 73 incorporating a high-intensity LED.

The head 30 further comprises an L-bracket 80 having an integrally-formed back-plate 81 and riser-plate 82, oriented at right angles to one another, and each with screw holes formed therein. A first pair of screws 83 threaded through the screw holes of the back-plate 81 hold the L-bracket against the rear wall 44 of the body portion 31, and a second pair of screws 84 threaded through the riser-plate 82 couple the L-bracket 80 with the second PCB 71.

Naturally, the rear wall 44 of the body portion 31 defines a set of screw bores into which screws to mount the L-bracket 80 and first PCB 61 are threaded.

When the second PCB 71 and the riser-plate 82 are assembled together, they effectively form the second planar support for the path beam light source 73. This second support occupies an area along a horizontal plane that is smaller than that of a corresponding part of the interior of the light chamber 51 that accommodates the second support. Thus the second support does not fully compartmentalise the light chamber 51 a U-shaped gap being defined around it. Thus light travelling transverse to that horizontal plane can bypass the second support and air carrying heat from electrical components, such as the light sources, can flow around the second support, and so heat is distributed more easily throughout the light chamber 51.

Referring to Figure 7, which is an enlarged sectional schematic side view of part of the head of the bollard of Figure 6, the path beam light source 73 is in the form of an LED that is capable of outputting a luminous flux of approximately 300 lumen. The path beam light source 73 is effectively mounted upside-down, with its optical axis directed vertically downward, broadly aligned with the longitudinal axis X of the bollard 1 as a whole and perpendicular relative to a plane formed by the second PCB 71 on which the path beam light source 73 is mounted.

The path beam light source 73 itself has a substantially regular radiation pattern that is rotationally symmetrical about its optical axis. Its maximum intensity point, or peak beam angle, is at 0 degrees (i.e. along the optical axis). Additionally, the full angular width of the radiation pattern at the half maximum intensity point (also referred to as the beam angle) is approximately 110-120 degrees. A suitable path beam light source for use with the present embodiment is manufactured by Osrame, for example the LED referred to as Osrame Square -of type GW CSSRM2.PM.

The path beam light module 70 also comprises a light guide 74 that mounts over the path beam light source 73 encapsulating it. The light guide 74 comprises diffracting structures that modify the light distribution of the path beam light source 73 asymmetrically so that most of the light emitted by the path beam light source 73 is directed both axially downward and forward, and so out from the light window 50 below the diffuser pane 35. In particular, the path beam light source 73 and light guide 74 combined together shifts the peak beam angle emitted by the path beam light module 70 as a whole to around 45-60 degrees relative to the vertical. Additionally, the beam angle is narrowed. A suitable light guide for use with the present embodiment is manufactured by LEDIL®, for example the LEDIL® Strada-FT.

Referring back to Figure 4, the diffusing reflector 36 is constructed from a single integrally-moulded piece of optical grade polycarbonate that is white in colour, and provides a diffuse but highly light-reflective surface having a reflectivity of greater than 98%. In other words, the diffusing reflector 36 exhibits substantially Lambertian reflectance. The diffusing reflector 36 comprises an integrally-moulded rear panel 36a, a left side panel 36b, a right side panel 36c, a base panel 36d, a left rear rail 36e and a right rear rail 36f.

The panels of the diffusing reflector 36 are arranged to form a broadly cuboidal trough that, when fitted into the light chamber 51 is open at an upper and forward region. The rear panel 36a, the left side panel 36b and the right side panel 36c extend vertically upwardly from the edges of the base panel 36d which extends in a broadly horizontally-orientated plane, resting on the floor 46 of the light chamber 51 when fitted therein. The left side panel 36b and the right side panel 36c flare outwardly from both the rear panel 36a and base panel 36d toward the upper and forward regions. Insertion of the diffusing reflector 36 into place within the light chamber 51 thus necessitates a small deflection of the left and right side panels 36b, 36c. Accordingly, the diffusing reflector 36 can be conveniently located and held in place via an interference fit between the side panels 36b, 36c of the reflector 36 and side walls 43, 42 of the light chamber 50 of the body portion 31.

Referring to Figure 7, when the diffusing reflector 36 is fitted into place, the left and right rear rails 36e, 36f hold the rear panel 36a away from, but broadly parallel to an interior surface of the rear wall 44. A pocket is formed therebetween within which wires can be routed up from the through-hole 47 to the pairs of wire connectors 62, 72 of the first and second modules 60, 70. This ensures that those wires are kept to the rear of the head 30 and thus do not interfere with the light transmitted via the light window 50.

Referring to Figure 4, the rear panel 36a of the diffusing reflector 36 is interrupted at its upper end by a central notch 36g. This locates around the path beam light module 70 during insertion of the reflector 36 into place. Additionally, a left corner notch 36i and right corner notch 36j interrupt the upper, forward corners of the left side panel 36b and right side panel 36c respectively. These together define a pair of axially upwardly-facing ledges that align with the inner and rearward peripheral recess 53 of the pair of peripheral recesses when the reflector 36 is fully inserted.

Referring back to Figure 3, the external lens 34 is relatively smooth and flat on its outer exterior surface 34a which facilitates cleaning. In contrast, an inner surface 34b of the external lens 34 is ribbed defining vertical refracting columns which are shaped to spread light emitted from within the light chamber horizontally outwards. Thus, the external lens 34 allows light to be spread further in a direction up and down the pathway 2 along which the bollard 1 is installed.

The external lens 34 locates within an outer and forward peripheral recess 54 of the pair of peripheral recesses 53, 54 of the frame and is sealed into place during manufacture using adhesive. Ideally, a resilient gasket is also provided between the external lens 34 and the frame to protect against ingress of water. Naturally, such sealing of the external lens 34 is performed after installation of the other components of the lighting assembly into the light chamber 51. When so installed, the smooth exterior surface 34a of the external lens 34 is flush with that of the front wall 41 of the body portion 31 and so level with the generally flat front surface 21 of the bollard 1 as a whole.

The diffuser pane 35 is slightly narrower, and sits behind the external lens 34, locating within an inner and rearward peripheral recess 53 of the pair of peripheral recesses 53, 54 of the frame of the light window 50.

Referring to Figure 7, the diffuser pane 35 is maintained in position by being trapped between the external lens 34 and the inner peripheral recess 53. Moreover, the diffuser pane 35 is restrained at its axially-lower end by part of the diffusing reflector 36. In particular, when the diffusing reflector 36 is fitted into place the axially upwardly-facing ledges formed by the left and right corner notches 36i, 36j of the reflector 36 support an underside of the diffuser pane 35.

Accordingly, the diffuser pane 35 occupies the upper part of the light window 50. The light window 50 is, in effect, split into two portions; a first portion 50a that has the diffuser pane 35 positioned across it, and a second portion 50b below the first portion 50a which is not interrupted by the diffuser pane 35.

Moreover, the light chamber 51 behind the light window is also split accordingly into two: Rearward of the diffuser pane 35, a first volume of the light chamber 51 is defined, and rearward of the second portion 50b of the light window 50 a second volume of the light chamber 51 is defined. The first and second volumes are contiguous with one another along a boundary 57 that is level with a bottom edge of the diffuser pane 35, the boundary 57 being represented schematically in Figure 7 by a dotted line.

The path and lateral beam light modules 60, 70 are situated in the first volume, above the boundary 57, and the diffusing reflector 36 is mostly situated within the second volume of the light chamber below the boundary 57. A light void that is uninterrupted by the light modules 60, 70 or other structures is therefore formed below the boundary 57 between the diffusing reflector 36 and the second portion 50b of the light window 50.

In general, the lateral beam light module 60 is positioned substantially toward the rear of the light chamber 51, with each lateral beam light source 63 accommodated wholly within the first upper volume of the light chamber 51. Each lateral beam light source 63 is spaced from the diffuser pane the same distance as one another, and the optical axis of each being parallel with one another. Accordingly, these optical axes intersect with the diffuser pane 35 at regular intervals matching the distribution of these light sources 63 across the first PCB 61.

The path beam light module 70 is generally situated close to the boundary 57 between the first and second volumes of the light chamber 51. Moreover, the light guide 74 intersects the boundary 57, with the path beam light module 70 being situated axially upwards of the light guide 74 slightly above the boundary 57. Both the path beam light source 73 and the light guide 74 of the path beam light module 70 are situated away from the periphery of the boundary 57 and slightly forward of a midpoint of the boundary 57 -specifically centred vertically over a midpoint of the light void between the rear wall 36a of the diffusing reflector 36 and the second portion 50b of the light window 50.

In operation of the bollard 1, when the light modules 60, 70 are activated to generate light, the general position, arrangement and configuration of the components of the light assembly result in that generated light being cast forward of the bollard 1, with a relatively low-intensity, wide-angle and diffuse lateral beam being emitted through the diffuser pane 35, and a relatively high-intensity, narrow-angle, non-diffuse path beam being emitted through the second portion 50b of the light window 50 that is below and uninterrupted by the diffuser pane 35.

More specifically, a primary component of the lateral beam is emitted through the diffuser pane 35 and first portion 50a of the light window 50, and a secondary component of the lateral beam is emitted through the second portion 50b of the light window. However, the path beam in its entirety is restricted so that it is emitted only via the second portion 50b of the light window 50.

The light sources 63, 73 of both light modules 60, 70 subsist within the first volume of the light chamber 51, and so the light that forms the path beam or lateral beam originates there.

In Figure 7, a schematic depiction of a vertical section of an envelope 79 of the path beam is represented by a pair of dashed lines. These are shown diverging outwards from the light guide 74 that encapsulates the high-intensity path beam light source 73 of the path beam module 70. Moreover, the vertical angle of divergence of the path beam envelope 79 is restricted by the lower edge of the diffuser pane 35, and the lower edge of the light window 50. Accordingly, the path beam is effectively light that originates from the path beam light source 73, that passed via the light guide 74 out through the second portion 50b of the light window 50 without being significantly diffused.

It should be noted that whilst the light guide 74 diffracts the light originating from the path beam light source 73 of the path beam module 70 to generally guide a significant proportion of it in a forward, downward direction as indicated by the path beam envelope 79, the light guide 74 itself also does not significantly cause diffusion. It should also be noted that some of the light originating from the path beam light source 73 spills outside of the envelope 79 of the path beam. Upward and forward of the envelope 79 of the path beam, this passes through the diffuser pane 35. Downward and rearward of the envelope 79 of the path beam, this spill light from the path beam light source 73 meets the diffusing reflector 36. Either way, a proportion of the light originating from the path beam light source 73 of the path beam module 70 becomes diffused by these diffusing components, and thereby forms a component of the diffuse lateral beam emitted by the bollard 1. Accordingly, whilst the path beam light module 70 is primarily for generating the light of the path beam, it also contributes to the light of the lateral beam -especially the secondary component of the lateral beam that is reflected by the diffusing reflector 36 and emitted through the second portion 50b of the light window 50.

Additionally, as alluded to previously, a U-shaped gap is defined around the second support incorporating the second PCB 71 and the riser-plate 82, and so the second support does not completely separate the first and second volumes of the light chamber 51. Thus, a small amount of light originating from the lateral beam light sources 63 is able to bypass the second support into the second volume below the boundary 57, and so this too may be reflected and diffused by the diffusing reflector 36.

Figure 8 is sectional schematic side view of the bollard 1 and adjacent pathway 2 of Figure 1.

A pair of dashed lines represent the envelope 79 of the path beam as in Figure 7. A second pair of dashed-and-dotted lines represent a vertical section of a second envelope 78 of the lateral beam.

Due to the diffusing effect of the diffuser pane 35 and diffusing reflector 36, the second envelope of the lateral beam 78 has a significantly larger vertical angle of divergence than that of the path beam 79, being restricted by and diverging outwards from the top and bottom edges of the light window 50. This provides a softer and lower-intensity light than the path beam.

Notably, the diffusing reflector 36 is positioned and arranged relative to other components of the lighting assembly so that substantially all of the light that is externally visible through the second portion 50b of the light window 50, when viewed from a position outside the envelope 79 of the path beam is light that the diffusing reflector 36 has reflected and diffused. A typical viewing position, for example, would normally be above a horizontal plane level with a bottom edge of the diffuser pane 35.

Additionally, the light that the diffusing reflector 36 has diffused and reflected out through the second portion 50b of the light window 50 exhibits substantially uniform light intensity.

Thus, whilst light can escape undiffused from the light chamber 51, the angle of this is restricted so that this is only transmitted through the second portion 50b of the light window 50, and only via the downwardly-directed path beam. Viewing the second portion 50b of the light window 50 from an overhead position does not expose an observer to non-diffuse light.

Additionally, the diffused light that is emitted from the bollard 1 is spread relatively uniformly across the viewable surface of the light window 50. This minimises harsh contrasts in light intensity as would otherwise be experienced from unmodified point-light sources such as LEDs. This means that users of a pathway 2 alongside which the bollard 1 is installed and operated are not subject to uncomfortable glare.

The bollard 1 is only one metre in height, and so this is under the eye-height of almost all users of the pathway 2. Accordingly, the undiffused downwardly-directed path beam will not cause user discomfort, yet effectively illuminates a target area of a pathway 2.

The two-dimensional vertical angle depicted in Figures 7 and 8 of the envelope 79 of the path beam is only illustrative of the three-dimensional solid angle that the path beam envelope actually follows. In general, this three-dimensional solid angle is confined by a perimeter of the second portion 50b of the light window 50. As this perimeter is broadly rectangular in shape, and the path beam is not diffuse, the solid angle is approximately pyramidal in shape.

Similarly, Figure 8 is only illustrative of the three-dimensional solid angle that the lateral beam envelope follows. Nonetheless, from Figures 7 and 8, it is evident that the envelope 79 of the path beam is smaller than the envelope 78 of the lateral beam. Accordingly, the path beam is confined within a narrower volume than that of the lateral beam, with the path beam and the lateral beam overlapping with one another.

This overlap leads to an overall light output and distribution of the bollard 1. This has been measured and defined to further characterise the bollard 1 of the present embodiment as will now be discussed in relation to Figures 9 and 10.

Figure 9 is an isolux diagram representing the light distribution of the lighting bollard 1 of Figure 1 over a horizontal planar surface level with the pathway 2 shown in Figure 1. Each contour passes through points of common illuminance, the value of which in lux is provided against each contour. Four contours are shown representing 5, 2.5, 1 and 0.5 lux from inner to outer contour respectively. Gridlines of Figure 9 represent metres, with the light window 50 of the lighting bollard 1 at a position that is, at its highest point, one metre above the horizontal plane level with the pathway 2, and at a location centred over the lowermost central coordinate (0,0). From this diagram, it can be seen that, of the light that is cast in a direction towards the ground, substantially all is cast in a position forward of the bollard -and so on to the pathway 2. Moreover, this light is spread laterally along the length of the pathway more so than forward along the width of the pathway. Thus, the light output of the bollard 1 is better utilised for its intended purpose, with the light predominantly being focussed in a way that covers a large area of the pathway 2.

Figure 10 is a photometric polar chart illustrating light distribution of the lighting bollard of Figure 1. The radial distance from the centre of the challis proportional to luminous intensity, with the centre of the chart representing a luminous intensity of zero candela, and the outer ring of the chart representing a maximum luminous intensity of 176 candela emitted from the lighting bollard.

Intermediate rings represent 25%, 50% and 75% of the maximum luminous intensity from inner to outer respectively (i.e. 44, 88 and 132 candela respectively). Radial position represents an angle relative to an apex approximately located at a centre-point of the light chamber of the bollard. The chart conveys luminous intensity at a range of angles, and so provides a rough approximation of a three-dimensional photometric web. Radially-extending lines are angularly-spaced at 10 degree intervals for ease of reference.

Two plots are shown in Figure 10: a first plot with a smaller contour of the two and marked by a dashed-line outline, and a second plot with a larger contour and marked by a dotted outline. Both plots extend through a maximum candela point, with a value of 176 candela.

The first plot defines a range of luminous intensity values in candela at a range of angles within a vertical plane (i.e. vertical relative to the ground). This vertical plane bisects the centre-point of the light window, and extends through horizontal angles 10 and 190 degrees (relative to 0 degrees which extends perpendicularly away from the front planar surface of the bollard). This first plot broadly illustrates an elevational view of how light is distributed above and below the lighting assembly. For orientation reference, it should be noted that, in relation to the first plot only, a radial line extending from the centre of the chart (where the light window is located) to the: * 12 o'clock position (180 degrees) corresponds to an axially upward direction towards the sky; * 6 o'clock position (0 degrees) corresponds to an axially downward direction towards the ground; and * 3 o'clock position (90 degrees) corresponds to a direction parallel to the ground, and away from the front of the bollard where the light window is located.

By contrast, the second plot, with the larger and more symmetrical contour, broadly illustrates an overhead view of how light is distributed around the bollard, and more particularly, around and below the lighting assembly. Using an often-used standard in photometry plots, the second plot is referential to a "horizontal cone through vertical angle (60) max. candela".

By way of further explanation, the second plot defines a range of luminous intensity values in candela as measured from a range of positions on a conical surface as defined by a virtual cone. The virtual cone is a right circular cone with a vertical axis that is parallel to that of the longitudinal axis of the bollard 1, and thus perpendicular to the ground. The vertex of the virtual cone coincides with the apex that is approximately located at a centre-point of the light chamber of the bollard 1.

The half-angle formed between the vertical axis of the cone, and a line extending between the vertex and a point on the virtual cone's surface is approximately 60 degrees. This coincides with the maximum candela point, as can be inferred from the first plot. Thus the opening angle of the virtual cone can be inferred to be 120 degrees.

Accordingly, any angle represented by the chart of Figure 10, in relation to the second plot only, corresponds to the angle formed between two straight lines on the surface of the virtual cone, as viewed from above along the vertical axis of the virtual cone, with the lines intersecting at the vertex of the virtual cone.

In the expectation that the virtual cone intersects with the pathway alongside which the bollard is installed, the second plot confirms that light is typically cast from the light window on to the pathway over a relatively wide angle: Greater than 44 candela (>=25% of maximum luminous intensity) is spread over an angle of approximately 140 degrees, greater than 88 candela (>=50% of maximum luminous intensity) is spread over an angle of approximately 115 degrees, and greater than 132 candela (>=75% of maximum luminous intensity) is spread over an angle of approximately 95 degrees.

Figures 9 and 10 thus evidence the following general light distribution attributes: The luminous intensity behind the light window of the bollard is effectively zero. Thus light is cast forward from the bollard. Additionally, the luminous intensity as measured at any point within an upper quarter-space forward and above the centre-point of the light chamber of the bollard does not exceed 50% of the maximum luminous intensity of the bollard. Thus, it is evident that lateral beam produces less than 50% of the maximum luminous intensity of light cast by the bollard.

Conversely, all the points at which luminous intensity of the bollard will be measured to be within 50-100% of the maximum fall within a lower quarter-space that is forward and below the centre-point of the light window. The maximum luminous intensity of light cast by the bollard is thus predominantly generated by the downwardly-directed path beam.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the scope of the appended claims.

Claims

CLAIMS1 A pathway lighting bollard comprising an elevated head, the head comprising a light chamber within which light is operatively generated, and the head defining a light window through which said generated light is cast forward of the bollard in use, the head further comprising: a diffuser pane that is positioned across a first portion of the light window and through which a relatively low-intensity and diffuse lateral beam is emitted, wherein: a relatively high-intensity and non-diffuse path beam, for illuminating a pathway forward and below the head of the bollard, is emitted downwardly through a second portion of the light window uninterrupted by the diffuser pane.
2. The bollard of claim 1, wherein the first portion of the light window that is interrupted by the diffuser pane is situated above the second portion of the light window.
3 The bollard of claim 1 or claim 2, wherein the top of the light window is approximately level with the top of the bollard, and the bollard, when installed, has a height of less than 1.5 metres.
4. The bollard of any preceding claim, wherein the head is configured so that light escapes from the light chamber only via the light window.
The bollard of any preceding claim, wherein the light chamber defines a first volume situated rearward of the diffuser pane and a second volume situated rearward of the second portion of the light window, the second volume being contiguous with the first volume along a boundary, the boundary being level with a bottom edge of the diffuser pane.
6 The bollard of claim 5, wherein the head comprises a diffusing reflector that is situated, at least in part, within the second volume of the light chamber, the diffusing reflector being positioned and arranged to reflect and diffuse light passing into the second volume of the light chamber from the first volume of the light chamber so that substantially all of the light that is externally visible through the second portion of the light window, when viewed from a position above a horizontal plane level with a bottom edge of the diffuser pane, is light that the diffusing reflector has reflected and diffused.
7 The bollard of claim 6, wherein the light that the diffusing reflector has diffused and reflected out through the second portion of the light window exhibits substantially uniform light intensity, and represents a secondary component of the lateral beam.
8. The bollard of claim 6 or 7, wherein the head is configured to define an uninterrupted light void below the boundary and between the second portion of the light window and the diffusing reflector.
9 The bollard of any one of claims 5 to 8, wherein the light chamber houses a lateral beam light module having at least one lateral beam light source for generating the lateral beam, and a path beam light module having a path beam light source for generating the path beam, the first volume of the light chamber accommodating the path beam light module and the lateral beam light module.
10. The bollard of claim 9, wherein the path beam light source is situated at or near the boundary between the first and second volumes of the light chamber.
11. The bollard of claim 9 or 10, wherein the path beam light source is situated closer to a midpoint than an edge of the boundary between the first and second volume of the light chamber.
12 The bollard of any one of claims 9 to 11, wherein the path beam light source light is oriented transverse to the lateral beam light source, positioned to face away from the first volume and towards the second volume of the light chamber, and configured to direct substantially all the light that it generates into the second volume of the light chamber.
13. The bollard of any one of claims 9 to 12, wherein the path beam light module comprises a light guide for guiding most of the light generated by the path beam light source through the second volume and towards the second portion of the light window.
14. The bollard of any one of claims 9 to 13, wherein the lateral beam light module is configured and positioned relative to the diffuser pane so that an outwardly-facing surface of the diffuser pane exhibits substantially uniform light intensity distribution, the at least one lateral beam light source being positioned substantially toward the rear of the first volume of the light chamber.
15. The bollard of any one of claims 9 to 14, wherein the lateral beam light module comprises a set of lateral beam light sources, each lateral beam light source emitting light according to a substantially regular radiation pattern that is rotationally symmetrical about its optical axis, and the set of lateral beam light sources being positioned and oriented relative to the diffuser pane so that their respective optical axes intersect with the diffuser pane at regular intervals.
16. The bollard of claim 15, wherein the diffuser pane is substantially flat along a vertical plane, the set of lateral beam light sources are spaced at regular intervals to one another across a first planar support oriented substantially parallel to that vertical plane, each lateral beam light source is spaced from the diffuser pane at a distance substantially the same as another lateral beam light source of the set, and the lateral beam light sources are oriented with their respective optical axes being substantially parallel to one another.
17. The bollard of any one of claims 5 to 16, wherein the path beam light source is held on a second planar support that extends in a horizontal plane over an area smaller than that of the interior of the light chamber that accommodates it, thereby allowing light travelling within the light chamber transverse to that horizontal plane to bypass the second support.
18. The bollard of any preceding claim, wherein the head comprises an external lens that forms a seal across the light window between an exterior and interior of the head of the bollard, the external lens comprising a relatively smooth exterior surface, and an inner surface comprising refracting structures shaped to spread light passing through the light window via the external lens.
19. The bollard of any preceding claim, wherein the bollard comprises a stem, the head surmounting the stem, and the head being configured to physically and electrically decouple from the stem.
20. The bollard of any preceding claim, wherein the path beam is confined within a narrower volume than that of the lateral beam.
21. The bollard of any preceding claim, wherein an envelope of the path beam is confined by a perimeter defined by the second portion of the light window.
22. The bollard of any preceding claim, wherein the maximum luminous intensity of light cast by the bollard is predominantly generated by the path beam and the lateral beam produces less than 50% of the maximum luminous intensity of light cast by the bollard.
23. The bollard of any preceding claim, wherein in operation, the bollard emits light at its maximum luminous intensity at an angle between 90 degrees and 20 degrees, as measured in a vertical plane extending forward of the bollard, wherein 180 degrees corresponds to an axially upward direction towards the sky, and 90 degrees corresponds to a direction parallel to the ground, and away from the front of the bollard.
24. The bollard of claim 23, wherein the bollard, in operation, emits light at: its maximum luminous intensity at an angle of between 45 and 70 degrees; less than 50% of its maximum luminous intensity at an angle between 150 degrees and 90 degrees; less than 25% of its maximum luminous intensity at an angle less than 20 degrees or greater than 150 degrees; and less than 5% of its maximum luminous intensity at any angle less than 0 degrees or greater than 180 degrees.
25. A lighting assembly for a pathway lighting bollard, the lighting assembly comprising a light chamber within which light is operatively generated, the lighting assembly defining a light window through which said generated light is cast forward of the lighting assembly in use, the lighting assembly further comprising a diffuser pane that is positioned across a first portion of the light window and through which a relatively low-intensity and diffuse lateral beam is emitted, wherein a relatively high-intensity and non-diffuse path beam is emitted downwardly through a second portion of the light window uninterrupted by the diffuser pane.