GB2566108B - Variable beam angle lighting unit - Google Patents

Description

VARIABLE BEAM ANGLE LIGHTING UNIT

The present invention relates to a variable beam angle lighting unit suitable for mounting on a ceiling, wall, panel or other fixture, particularly but not exclusively within a cavity formed in the fixture. More particularly, but not exclusively, the present invention relates to a variable beam angle lighting unit comprising a LED lamp array.

Commonly available spotlights incorporate a lens or sets of lenses which to produce a light beam with a specific beam angle. If for example the beam angle is insufficient to illuminate a given area, the user must replace the spotlight with an alternative spotlight that provides the desired beam angle coverage.

Variable beam angle spotlights are commercially available and provide variable beam angles through use of a variable focal length lens arrangement, similar to the arrangement used with camera lenses. These arrangements are costly, greatly increase the size of the lighting unit and require moving parts which decreases the reliability of the spotlight.

Alternatively, spotlight beam angles may be controlled by restricting the passage of light through a variable aperture. These systems are unreliable however and result in loss of light output.

The present invention seeks to address the problems of the prior art.

According to the invention a light unit comprises: a housing having a central symmetry axis: a support located in the housing; a main lamp located axially on the support; a multiplicity of secondary lamps located on the support and arranged in one or more arrays around the main lamp; a front casing defining a central aperture; a light guide member located in the housing, the light guide member comprising: a main lens having: a main light inlet proximate the main lamp; and a main light outlet; the main lens being arranged to allow passage of light through die main lens and out of the central aperture; and one or more light guide elements located radially outwardly the main lens, each light guide element having: a light guide inlet proximate a secondary lamp array; and a light guide outlet: each light guide outlet being arranged to allow passage of light through the respective light guide element and out of the housing; the main lens being arranged to provide a main beam along the central symmetry axis with a main beam ancle. the one or more light guide elements being arranged to provide one or more outer peripheral beams radially outwardly of the main beam; wherein the light unit provides the main beam and the one or .more outer peripheral beams individually or in combination with each other; and wherein the main beam and the one or more outer peripheral beams are arranged to provide a composite beam with a beam angle greater than the main beam angle, A variable beam angle is achieved through use of the main lens and the one or more light guide elements. The main beam is directed alone the central svmmetry axis bv the main lens at a main beam angle selected to illuminate all or part of a room. If a user requires a wider beam angle, the user may provide light using a first array of secondary lamps to the light guide element located in contact with or adjacent the main lens. The light guide element provides the outer peripheral beam radially outwardly away from the central symmetry axis. The main beam and outer peripheral beam are arranged to provide a composite beam which a user may perceive as a single beam of light. Regulating the power supplied to the main lamp and/or secondary lamp array to brighten or dim the lamps may further enhance a user’s perception of a single beam (if light.

One or more further light guide elements may be provided within the light unit. For example a second light guide element may be positioned next to the first light guide element distal horn the main lens. The second light guide element receives light from a second array of secondary lamps which are positioned radially outwardly in contact with or adjacent the first array of secondary lamps radially outwardly from the main lamp. The main beam and outer peripheral beams are arranged io provide a composite beam which a user may perceive as a single beam of light. This arrangement may he repeated with further light guide elements and arrays of secondary lamps. Regulating the power supplied to the main lamp and/or one, two or more secondary lamp arrays to brighten, or dim the lamps may further enhance a user’s perception of a single beam of light.

The secondary lamps may be provided on a strip of material. Preferably the strip of material is annular. The strip of material may be straight or polygonal. The strip of material may be attached to the support, for example by adhesive. The strip of material may be composed of n polymeric material.

The light unit of the present invention can be used in rooms with varying roof heights. For example, a narrower beam of light is preferred in a room with a high roof as this reduces the spread of light and thereby increasing the brightness at the floor level or at a display unit. Therefore only the main, beam may be used. In contrast, a wider beam angle is preferred in a room with a low roof as this increases the spread of light adequately before the light reaches the floor. There tore, both the main beam and one or more peripheral beams may be used.

Hie light unit of the present invention can also be used in different locations within a room. For example, a wide beam angle may be preferred if the light unit is positioned in a central location. Alternatively, namiw beam angles are used when the light unit is positioned close to a wall or comer.

The light unit of the present invention also allows the unit to provide general lighting using a wide beam and for spot lighting using a narrow beam.

Increasing the number· of light guide elements enables the user to provide a beam with progressively increasing beam angles. Preferably, 2 to 6 light guide elements may be used in the light unit. In an embodiment 4 to 6 light guide elements may be used in the light unit.

When using in the narrow beam configuration only the main lamp may be powered. All light produced by the light unit will accordingly be directed through the main lens to produce a main beam with a main beam angle.

When using in the wide beam angle configuration, both the main lamp and the one or mom arrays of secondary lamps may be powered. Light is projected through both the main lens and the one or more light guide elements to produce a composite beam comprising a main beam surrounded by an outer beam. The composite/collective beam has a beam angle greater than the main beam angle. I he above arrangement has the advantage that there are no moving parts. This may increase reliability and reduces manufacturing complexity and production costs. Also, as variable beam angles are not provided as when one uses a variable focal length lens arrangement, the unit size of the light unit may be decreased. Decreasing the unit size also may allow the light unit to he substantially flush with a ceiling, wall, panel or other fixture. A further advantage of decreasing the unit size is that height of the unit may be decreased which allows the unit to be used in smaller cavity spaces.

In an embodiment, a constant power supply, for example 10W, may be provided to the main and secondary lamns to ensure a consistent brightness outnut. In an alternative Λ ‘•«'A embodiment, powering the one or more arrays of secondary lamps increases the overall power of the unit and thereby increases the brightness. This may be desirable in commercial settings where application of a wide beam is typically needed to illuminate a larger area.

In a further embodiment, power distribution to the main lamp and the one or more arrays of secondary lamps is controlled by a driver to ensure optimal light quality. The driver may comprise an adjustable power supply adapted to regulate the power delivered to the main lamp and/or arrays of secondary lamps, Accordingly, the main lamp may be dimmed and the one or more arrays of secondary lamps may be brightened. Alternately, the main lamp may be brightened and the one or more arrays of secondary lamps may be dimmed. This reduces spotting or separation of the main beam and the one or more peripheral beams when power is supplied to both the main lamp and the one or more arrays of secondary lamps. This may help to give an overall impression to a user that the beams have been focussed. This may also allow engineers to control the mixing point of the light, beams to improve the quality of the light at the floor level. T he mixing point may be heightened or lowered depending on the distance of the lamn from the floor.

A

The light unit may comprise a LED lamp array. Alternative embodiments may employ halogen bulbs, OLED lamps or incandescent lamps.

In exemplary units the main beam may be provided at an angle between 30° to 50°, for example between 35° to 45°, or for example about 40Greater main beam angles may also be used.

The one or more peripheral beams may be provided as symmetrical beam rings. These beams may have uniform luminosity.

The one or more peripheral beams may be provided at an acute or obtuse angle relative to the central symmetry axis. Preferably the one or more peripheral beams are angled between 40° to 70°. preferably between 55° to 65°, even more preferably 60°. Greater peripheral beam angles may also be used.

Preferably, a first peripheral beam is angled to lie proximal to the main beam. Alternatively, the first peripheral beam is angled to partially overlap with the main. beam.

Preferably, a second peripheral beam is angled to he proximal to the first peripheral beam. Alternatively, the second peripheral beam is angled to partially overlap with the first peripheral beam. These arrangements can be applied to third and subsequent peripheral beams.

The composite beam angle may be between 30° to 70°, preferably between 40° to 60°. Greater composite beam angles may also be used.

The light unit may further comprise a lamp dividing wall located in the housing, the lamp dividing wall having an axial array of projections extending away from the support towards the light guide member to prevent the passage of light from the main lamp to the one or more light guide elements and from the secondary lamps to the main lens.

The projections of the lamp dividing wall may extend upwardly into a recess or channel between the main lens and the light guide elements. The projections of the lamp dividing wall may also extend upwardly into a recess or channel between each of the light guide elements. Alternatively, the projections may extend upwardly to abut the main lens or the light guide elements.

Preferably the lamp dividing wall and the front casing are integrally formed. Alternatively the lamp dividing wail is provided separate to the front casing. Alternatively, the lamp dividing wall may be positioned directly onto the support so that the projections extend into the front casing.

Tlte lamp dividing wall may define an axial hub dimensioned to receive the main lamp. The projections of the lamp dividing wall may extend radially outwardly away from axial aperture, in a spoked arrangement. The projections may be extend axially so that they contact the sides of the front casing or the housing. The projections may extend radially outwardly away from axial aperture through multiple light guide elements. Alternatively, the lamp dividing wall may comprise a co-axial array of the above hub-projection arrangement.

The light guide dements may have an annular body extending radially outwardly away from the light guide inlet towards the light guide outlet. The one or more light guide elements may further comprise an annular flange extending from the annular body. The light guide outlet may be located in the annular flange, preferably on a periphery of the flange. The light guide may be generally L-shaped in cross section.

The light guide elements may be rotationally symmetrical about the central symmetry axis. The light guide elements may be circular. Alternatively the light guide elements may be oval or may have n-fbld symmetry, wherein n is an integer, about the central axis.

The light guide outlet may be directed radially outwardly of the housing.

The main lens and the one or more light guide elements may be composed of an acrylic polymer, for example an acrylic polymer or glass, polycarbonate, glass, or other high refractive index material wherein the refractive index is selected so as to achieve total internal reflection of light passing from the light inlet to the light outlet. Alternatively, the main lens and the one or more light guide elements may be made from a composite of the above materials.

The main lens may have an annular body extending radially outwardly away from the main light inlet towards the main Light outlet. Preferably the main lens is cone shaped.

The surface of the main lens and the one or more light guide elements may have a reflective, opaque or textured finish to improve transmission of light through the lens structures.

In an embodiment the main lens, one or more light guide elements and one or more dividers are provided as a unitary construction. Preferably the dividers are embedded within the material forming the light guide member. This arrangement ensures optical quality and avoids spotting.

In an alternative embodiment the main lens, one or more light guide elements and one or more dividers are provided as separate components. In a further embodiment the main lens and the one or more light guide elements are provided as separate components and the main lens or the one more light guide elements are provided as a unitary construction with the one or more dividers.

Each light guide element may have a single light guide inlet and outlet. The single light guide inlet being arranged proximate an array of secondary lamps.

Alternatively, each light guide element may have a light guide inlet arranged proximate a single secondary lamp. A plurality of light guide elements may be used for an array of secondary lamps. For example a circular array of light guide elements may be located over a circular array of secondary lamps. Each of the light guide elements may therefore produce separate peripheral beams.

In an exemplary embodiment a divider may be located between the main lens and the light guide element. This prevents passage of light from the main lens to the light guide element and from the light guide element to the main lens.

If more than one light guide element is present then further dividers may be used between each of the light guide elements. For example, a divider may be positioned between two adjacent light guide elements. The dividers prevents passage of light between the Light guide elements.

The divider may be configured to channel the main beam outwardly to provide the main beam angle.

The divider may be configured to channel the outer periphery beams outwardly at a given angle.

The one or more dividers may be arranged to contact the support to prevent light from escaping laterally, relative to the central symmetry axis, from the main and secondary lamps.

The one or more dividers may be arranged to extend radially outwardly away from the support towards the front casing. The one or more dividers may he composed of a reflective, opaque, frosted or textured sheets or films. The dividers may be composed of a single sheet of material or an array of laminar sheets of material.

The dividers may be provided as a coating on the main lens and/or on one or more of the light guide elements.

The dividers may be composed o( polymeric material, for example polypropylene, acrylonitrile butadiene styrene, or polycarbonate. Alternatively, the dividers may be composed of aluminium, for example aluminium sheets or tin-foil.

Furthermore, the divider material may optimise internal reflection. For example providing a reflective, opaque, frosted or textured material may improve dispersion of light by internal reflection within the light guide elements. This has the beneficial result of providing more uniform periphery beams.

Providing a frosted divider with an unpolished or matt appearance may be achieved by not polishing the guide after removal from a mould. The moulded guide may be sandblasted to remove tooling marks but not subsequently polished. Tire provision of a frosted surface has the advantage of reducing manufacturing costs. T he radius of the surface facing towards the central axis may have a maximum value having a central radius curving from the light guide inlet towards the outer flange surface, in order to optimise total internal reflection m use. T he width in a radial direction of the light guide inlet is greater than the width in the axial direction of the light guide outlet in order to concentrate the light beam as it passes from the light guide inlet to the light guide outlet.

One or both of the light imide inlet and liuht guide outlet surfaces may be textured to KJ KJ 'w.' <1- «· increase uniform and efficient transmission of light from the outlet.

A main LED may provide a full range of white light colour using a LED driver circuit assembly and a dual colour LED chin of 27OOK (commonly referred to as 3000K) and 6500K (commonly referred to as 6000K). Mixing of these two colours via the driver’s circuit assembly provides a colour contrast temperature (CCT) adjustable from 2700K to 6500K.

In an exemplary embodiment the secondary lamps may comprise a circular array of 16 LED chips with a total power of 2W. Red/Blue/Green RBG or alternating 2700K and 6500K LEDs may be used.

The primary light brightness may be controlled by increasing the power from 0 to 1OW. The secondary light brightness may be controlled by increasing the power from 0 to 2W, this power being distributed across all 16 LED chips.

The primary and secondary lights may be independently or jointly controlled to change their colour and brightness.

The chips are preferably positioned to point directly downwards parallel to the central axis. This has the advantage of minimising product depth, maintaining similar aesthetic appearance to a standard downlight assembly. Simplified construction is achieved. Peripheral lighting using the light guide which in a preferred embodiment has a toroidal configuration and is L-shaped in cross section.

Remote control may be provided using computer software or a smart device application. Commands from the software or device may be communicated to an individual light unit or to groups of light units by wireless communication methods such as Bluetooth (Registered Trade Mark) or WiFi (Registered Trade Mark). However signals may also be sent through the mains power supply. The light unit may be additionally/alliteratively controlled by a physical switch on the unit, by a wall switch or by a control plate. A heat sink may be located in thermally conductive communication with the support. The heat sink may be located in contact with a rear surface of the support, so that the heat sink conducts heat directly from the main and secondary LEDs in use.

An intumescent seal may be provided between the heat sink and the housing. The intumescent seal may be positioned to expand inwardly into the housing when heated to a sufficient temperature.

Use of a light unit in accordance with the following invention provides many benefits including the following: .1. remote control of the lights including on/off, colour and brightness control; 2. individual and group control of the lights; 3. the ability to vary the beam angle between narrow and wide beam settings; a I 4. the ability to moderate the amount of power applied by the main lamp and the secondary lamps.

Example 1 - Brighter spot lights

It may be preferential to have a brighter spot light when using a narrow beam to better illuminate a point of interest, for example illuminating a display stand in a museum, retail or wholesale outlet. To achieve this, a total power deliver of 30W may be used in the narrow beam setting. When using the wide beam setting the total 30W power can be distributed between modules.

The following table provides an example using a unit with 60, 30 and 15-degree segments.

Example 2 - Brighter ambient lights

It may be preferential to increase the brightness of the light as the beam angle increase to ensure an even amount of light is always delivered to the floor regardless of how much area the light is spread over, for example in a shop. To achieve this, a consistent amount of power is delivered to lens segment unit.

Tire following table provides an example using a unit with 60, 30 and 15-degree segments.

Example 3 Creating the effect of fully adjustable beam angles

The product and resulting beam may have fixed beam angles that can be selected. For example, 5 setting might be 70, 60, 50. 40, 30 degrees. However, when moving between settings it is possible to simulate a full adjustable angle through the distribution of power to each: segment.

The following table provides an example of power distribution to each LED chip group as die beam angle is lowered from 7'0 --- 30 degrees.

Example 4 - Beam mixing

By adjusting the powered delivered to each lens segment that can be improved. For example on a product with two beam angles - 60, 35 and 15 degrees, when using 60 degrees die chips used in the outer lens section can be increased in brightness ensuring even light distribution throughout the beam.

One following table provides an example using a unit with 60, 30 and 15-degree segments.

The point at which the light focuses as a perfect “mix” can also be adjusted by manipulating the power supplied to each segment. This is useful as a single unit can be installed into any height celling and a perfect “mix” be achieved at floor level.

The invention if further described by means of example but not in any limitative sense with reference to the accompanying drawings, of which:

Figure 1 is a cross sectional view of the light unit;

Figure 2 is an exploded view of the light guide member shown in Figure 1;

Figure 3 is an exploded view of the light unit;

Figure 4 is a perspective view of t he light unit: and

Figure 5 is a cross sectional view of the light unit showing the mam and composite beam angles. T he same reference numerals are used to denote like components in each of the Figures.

The light unit shown in the Figures comprises a housing (1) having a central axis of symmetry and includes a rear portion (2) and a radially outwardly extending flange (3). The

rear portion (2.} defines a central aperture (4) with a convoluted outer periphery comprising inwardls' extending projections with gaps between the projections. A pair of outwardly extending connecting members (5) extend from the rear portion (2). The housing ill is arranged to fit into an aperture in a ceiling panel or other fascia (not shown) with the flange (3) overlying the surface of the fascia to conceal the aperture. The light unit is secured to the fascia by means of two spring clips (6) which are configured to attach to the connecting members (5).

The light unit further comprises a main LED chip lamp {"} mounted centrally on a support (8) located in the rear of the housing (I). A multiplicity of secondary LED chip lamps (9) are mounted on the support (8) in a circular array around the main LED chip lamp (7). A heat sink (J 0) having cooling fins (111 Is mounted on the rear surface of the support i8s and provides cooling for both the -main (7) and secondaiy (9) LED chip lamps. .A guide (12) for a power supply cable is provided at the side of the heat sink (Kb. An intumescent seal ring (13) is located on the rear portion of the housing (I) so dial die intumescent seal ring (13) lies against the flange (31 of die housing (1). A further annular intumescent seal (14 defining a central aperture (15) with a convoluted outer periphery comprising inwardly extending projections with gaps between the projections is located between the heat sink (1(0 and the rear portion (2} so that the central apertures (4, 15) can al least partially overlap.

The light unit further comprises a front casing (16) having a lamp dividing wail (17) and a radially outwardly extending annular flange (18). The lamp dividing wall (17) defines an axial cylindrical main central aperture (19) within which the main LED chip lamp (7) is axially located and a multiplicity of secondary apertures (20} in a radially outwardly array around the main central aperture (19} within which the secondary LED chip lamps (9) are located. The lamp dividing wall (17) further comprises an array of radially extending projections (21) located between: each of the secondary apertures (20). Each of the projections (21} project upwardly towards tire annular flange (18). The lamp dividing wall (17) is positioned to contact the support (8) so that light from the secondary LED chip lamps (9) and the main LED ehip lamp 17) cannot mix within the housing. A light guide member (22) is shown in greater detail in Figure 2 and comprises a main lens (23) and a light guide element (24), The main lens (23) is dimensioned to be received within the light guide element (24). The main lens (23) is cone shaped and comprises an annular body extending radially outwardly away from a main light inlet (25) towards a main light outlet (26), The main light inlet (25) may be located in contact with the main LED chip lamp (7) or may be arranged in proximate spaced relation to the main LED chip lamp (7). The main lens (23) may be made of an acrylic polymeric resin.

The light guide element (24) has an annular or toroidal body with a radially inner surface (28) which extends in a smooth curve having a maximum radius from a light guide inlet (29i towards an annular flange (30) having a cylindrical light guide outlet (31). The light guide inlet (29) may be located in contact with the secondary LED chip lamps (9) or may be arranged in proximate spaced relation to the secondary LED chip lamps (9). Tire surface of the light guide outlet (31) extends coaxially with the centra! axis of symmetry of tire unit. The light guide element (24) may be made of an acrylic polymeric resin.

An outer surface (33) of the light, guide element (24) has a stepped configuration to allow the guide to be accurately located within the housing (1) in contact with the extended flange (3) overlying the fascia surface.

The light unit further comprises a divider ¢34) formed from a single sheet of material in the shape of a cone. The divider (34) is adapted to be located between the main lens (23) and die light imide element (24). The divider (34) may have a curvature that corresponds to the curvature of the main lens (23) and the curvature of the inner surface (.28) of the light guide element (24), Such an arrangement may prevent movement of the main lens (23) and light guide element (24) relative to one and other. Alternatively, the divider (34) may be arranged to partial contact the main lens (23) and the light guide element (24). The divider (34) may also be arranged so that it does not contact the main lens (23) or the light guide element (24). The divider (34) may be composed or a reflective, opaque or textured material. The surface of the main lens (23) and the light guide element (24) may have a reflective, opaque or textured finish to improve transmission of light through the lens structures.

The divider (34) is positioned between the main lens (23) and the light guide element (24) to prevent light from escaping from the sides of the main lens (23) and the light guide element (24).

In use power is applied to the main LED chip lamp (7) and light emitted from the main LED chip lamp (Ί) is directed through the main lens (23) to provide a main beam with a beam angle, in this embodiment 40”. If a user wishes to widen the beam angle the user provides power to the secondary LED chip lamps (9) and light emitted from the secondary LED chip lamps (Q) is directed through the fight guide element :.24) to provide a peripheral radially outwardly away from the central symmetry axis, The main beam and tfie peripheral beam are arranged to provide a composite beam with a beam angle greater' than the main beam angle, in this embodiment 60°,

Various modifications will be apparent to a person skilled in the art. In an embodiment the heat sink (10) may include forwardly extending projections (not shown) arranged to pass through an array of gaps (not shown) in the rear portion (2) of the flange (3) and into thermal contact with the rear surface of the support (8).

Claims (19)

1. A light unit comprising: a housim; having a central syrmnetry axis: l.-· <P V ν' a support located in the housing; a main lamp located axially on the support: a multiplicity of secondary lamps located on the support and arranged in one or more arrays around the main lamp; a front casing defining a central aperture; a light guide member located in the housing, the light guide member comprising: a main, lens bavins: a main Heht inlet nroximate the main lamp: and a main limit outlet; w > the main lens being arranged to allow passage of light through the main lens and out of the central aperture; and one or more light guide elements located radially outwardly the main lens, each light guide element having: a light guide inlet proximate a secondary lamp array; and a light guide outlet; each light guide outlet being arranged to allow passage of light through the respective light guide element, and out of the housing; the mam lens being arranged to provide a main beam along the central symmetry axis with a main beam angle, the one or more light guide elements being arranged to provide one or more outer peripheral beams radially outwardly of the main beam; wherein the light unit provides the mam beam and the one or more outer peripheral beams individually or in combination with each other; and wherein the main beam and the one or more outer peripheral beams are arranged to provide a composite beam with a beam angle greater than the main beam angle.

2. A light unit as claimed in claim I, wherein the one or more peripheral beams are provided at an acute or obtuse angle relative to the central symmetry axis.

3. A light unit as claimed in claim 1 or 2, wherein the composite beam angle is between 30° to 70°.

4. A light unit as claimed in claim 3, wherein the composite beam angle is between 40° to 60°.

5. A light unit as claimed in any preceding claim, further comprising one or more dividers located between the main lens and each of the one or more light guide elements; wherein the one or more dividers prevents passage of light from the main lens to the one or more light guide elements and from the one or more light guide elements to the main lens.

6. A light unit as claimed in claim 5, wherein the dividers are cone shaped.

7. A light unit as claimed in claim 5 or 6, wherein the one or more dividers are arranged to extend radially outwardly away from the support towards the front casing.

8. A light unit as claimed in any of claims claim 5 to 7, wherein the one or more dividers are arranged to contact the support.

9. A light unit as claimed in any of claims 5 to 8, wherein the one or more dividers are composed of a reflective, opaque, frosted or textured material.

10. A light unit as claimed in any preceding claim, wherein the one or more light guide elements have an annular body extending radially outwardly away from the light guide inlet towards the light guide outlet.

11. A light unit as claimed in claim 10, the one or more light guide elements further comprising an annular flange extending from the annular body, wherein the light guide outlet is located in the annular flange.

12. A light unit as claimed in claim 11, wherein the light guide outlet is located on a periphery of the annular flange.

13. A lieht unit as claimed in anv oreceding claim, wherein the main lens has an annular body extending radially outwardly away front the main light inlet towards the main light outlet.

14. A lii’ht unit as claimed in anv of claims 5 to 9, wherein the main. lens, one or more light guide elements and one or more dividers are provided as a unitary construct.

15. A light on.it as claimed in. any of claims 5 to 9, wherein the main lens, one or more light guide elements and one or more dividers are provided as separate components.

16. A light unit as claimed in any of claims 5 to 9, the main lens and the one or more light guide elements are provided as separate components, wherein the main lens or the one more light guide elements are provided as a unitary construct with the one or more dividers.

17. A light unit as claimed in any preceding claim, further comprising a lamp dividing wall located in the housing, the lamp dividing wall having an axial array of projections extending away from the support towards the light guide member to prevent the passage of light from the main lamp to the one or more light guide elements and from the secondary lamps to the main lens.

18. A lieht unit as claimed in anv preceding claims, wherein the lieht guide member is rotationally symmetrical about the central symmetry axis.

19. A light unit as claimed in any preceding claim, wherein the light guide member is composed of acrylic polymer.