WO2013182989A1 - Lighting device comprising a bearing device - Google Patents

Lighting device comprising a bearing device Download PDF

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Publication number
WO2013182989A1
WO2013182989A1 PCT/IB2013/054597 IB2013054597W WO2013182989A1 WO 2013182989 A1 WO2013182989 A1 WO 2013182989A1 IB 2013054597 W IB2013054597 W IB 2013054597W WO 2013182989 A1 WO2013182989 A1 WO 2013182989A1
Authority
WO
WIPO (PCT)
Prior art keywords
heat spreading
spreading device
lighting device
light units
bearing device
Prior art date
Application number
PCT/IB2013/054597
Other languages
French (fr)
Inventor
Johannes Maria Thijssen
Andreas Aloysius Henricus DUIJMELINK
Original Assignee
Koninklijke Philips N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips N.V. filed Critical Koninklijke Philips N.V.
Publication of WO2013182989A1 publication Critical patent/WO2013182989A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V14/00—Controlling the distribution of the light emitted by adjustment of elements
    • F21V14/02—Controlling the distribution of the light emitted by adjustment of elements by movement of light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V19/00—Fastening of light sources or lamp holders
    • F21V19/02—Fastening of light sources or lamp holders with provision for adjustment, e.g. for focusing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2103/00—Elongate light sources, e.g. fluorescent tubes
    • F21Y2103/10—Elongate light sources, e.g. fluorescent tubes comprising a linear array of point-like light-generating elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2105/00—Planar light sources
    • F21Y2105/10—Planar light sources comprising a two-dimensional array of point-like light-generating elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the invention relates to a lighting device comprising a bearing device and one or more light units, each of the one or more light units comprising a first heat spreading device and at least one point light source mounted on the first heat spreading device.
  • Lighting devices of the above-mentioned type are widely used for lighting applications, in which a highly controlled and customizable light distribution is desired. Such applications include particularly spotlights, tiltable spots and spots that require an adjustable beam angle. Such lighting devices are suitable for both professional applications and consumer applications.
  • each LED of the lighting device is provided with an associated optical element, which is adjustable.
  • the associated optical element, which is adjustable is preferably a reflector.
  • the LEDs are mounted on a circuit board.
  • the associated optical elements are mounted adjacent to each LED.
  • the reflectors are individually adjustable e.g. by means of a setscrew.
  • the assembly of circuit board, LEDs and associated optical elements are arranged in a housing.
  • the prior art lighting devices have at least two disadvantages: at least when such lighting devices are adjusted, the LED and its associated optics, or at least the adjustable optical element, protrudes from the surface of the housing, which is not preferred for aesthetical reasons.
  • Adjustable lighting devices which are adjusted within a housing and remain completely behind the surface area of the housing usually illuminate the inside of their own housing, resulting in a disturbed light distribution, a low optical efficiency and sometimes also causing glare.
  • lighting devices including a heatsink are tilted, this usually means a relatively large volume has to move.
  • the thermal resistance is relatively high.
  • the first heat spreading device comprises at least one part having an at least partially circular cross section and a centre of rotation
  • the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that each of the one or more light units is rotatable with respect to the bearing device around the centre of rotation of the at least one part of the first heat spreading device.
  • lighting devices according to the invention may in particular be used for tiltable spots and for spots that require an adjustable beam angle and/or light distribution. Furthermore, lighting devices according to the invention are particularly advantageous when used in recessed spots and lighting systems where movement of the housing is not preferred and where a limited height is preferred.
  • the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that the first heat spreading device forms an axle and the bearing device forms an axle-box.
  • the interface between the first heat spreading device and the bearing device functions as a mechanical bearing and a thermal interface at the same time, which provides for a particularly simple construction of the lighting device.
  • the lighting device comprises two or more light units, and the first heat spreading device of each of the two or more light units are connected in such a way that the two or more light units are rotatable simultaneously with respect to the bearing device and each around the centre of rotation of the at least one part of the first heat spreading device.
  • the at least one part of the first heat spreading device comprises an at least partially circular cross section and at least one axis of rotation extending through the centre of rotation, and the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that each of the one or more light units is rotatable with respect to the bearing device around the at least one axis of rotation of the part of the first heat spreading device.
  • connection is provided by means of a mechanical connecting means, such a connecting rod or a connecting plate, which ensures a very simple way of establishing the connection.
  • the mechanical connecting means has a variable size in at least one direction.
  • the size of the connecting means in principle in any possible direction, but primarily in one or more of the width, length and a diagonal direction, further possibilities for varying the light distribution of the lighting device is provided. Thereby a large variety of light distributions, such as e.g. a narrow beam, a wide beam and a batwing-shaped beam, may be obtained.
  • the size may be variable in a linear or non-linear manner.
  • each first heat spreading device is connected to the connecting means by means of an intermediate device, such as at least one pin, thereby providing a particularly simple and robust connection between the connecting means and the first heat spreading device.
  • each first heat spreading device may be identical, e.g. all being cylindrical pins.
  • each first heat spreading device may be connected to the connection means in such a way that the intermediate device is provided with its own path relative to the connection means.
  • the connection means may in this case be pins, each pin being provided with a specific form or shape, such as e.g. bent, curved, S-shaped, angled or the like. Thereby the light distribution may be changed in a way which is related to the angle of rotation, which may result in e.g. a small beam or an asymmetric beam.
  • the connecting means may be a camshaft.
  • the first heat spreading device is cylindrical and the bearing device comprises a receiving means, such as a cylindrical recess or bore, adapted for receiving the first heat spreading device.
  • the first heat spreading device is spherical and the bearing device comprises a receiving means, such as a spherical recess or bore, adapted for receiving the first heat spreading device.
  • the lighting device is provided with a particularly simple relationship between the first heat spreading device and the bearing device, thus obtaining a particularly simple and durable construction.
  • the bearing device forms a second heat spreading device and/or a heat sink, and/or the bearing device is made of more than one part.
  • a lighting device is obtained which provides for more possibilities for providing the lighting device with different overall shapes.
  • the lighting device furthermore comprises at least one thermal interface material arranged between the first heat spreading device and the bearing device, and/or at least one additional heat sink connected to the bearing device.
  • at least one thermal interface material arranged between the first heat spreading device and the bearing device, and/or at least one additional heat sink connected to the bearing device.
  • the at least one light unit comprises optical elements such as e.g. a reflector, a collimator or a diffusor.
  • optical elements such as e.g. a reflector, a collimator or a diffusor.
  • the bearing device forms the housing, which provides for a lighting device having a particularly simple construction.
  • the first heat spreading device of each of the one or more light units is made of an electrically conductive material and is adapted for providing an electrical connection of the at least one or more light units to one or more other light units directly and/or by means of electrical connection means and/or to an electrical connecting means for connecting the lighting device to a power supply and/or to a power supply directly.
  • Fig. 1 shows an exploded view of a first embodiment of a lighting device according to the invention comprising a plurality of light units.
  • Fig. 2 shows an exploded view of the first embodiment of a lighting device according to the invention comprising one light unit.
  • Fig. 3 shows a perspective view of the lighting device according to Fig. 1 in an assembled state.
  • Fig. 4 shows an exploded view of a second embodiment of a lighting device according to the invention comprising a plurality of light units.
  • Fig. 5 shows a cross sectional view of a row of light units of the lighting device according to Fig. 4.
  • Fig. 6 shows a perspective view of the lighting device according to Fig. 4 in an assembled state.
  • Fig. 7 shows a cross sectional view seen from below of the lighting device according to Fig. 1 in which the first heat spreading devices are adapted for providing an electrical connection of said light units.
  • Fig. 8 shows a cross sectional view of one of the light units of the lighting device according to Fig. 4 in which the first heat spreading device is adapted for providing an electrical connection of the light unit.
  • Figs. 1 to 3 show a first embodiment of a lighting device according to the invention.
  • the lighting device 1 shown in Figs. 1 and 3 comprises a bearing device 5, 5a, 5b and nine light units 2.
  • Each of the nine light units 2 comprises a first heat spreading device 4 and two point light sources 3a, 3b mounted on the first heat spreading device 4.
  • Fig. 2 shows a version of the lighting device 1 comprising just one light unit 2, but otherwise having the same construction as the lighting device 1 shown in Figs. 1 and 3.
  • the lighting device may comprise any feasible or desirable number of light units, including just one light unit.
  • the number of point light sources 3 (Fig. 3) in each light unit may be any feasible or desirable number.
  • the point light source 3 may in principle be any feasible type of point light source, such as e.g. a light source with a pin hole arranged in front thereof, or an array of point light sources.
  • a linear light source such as e.g. a linear Chip-On-Board LED, may be used.
  • the at least one point light source 3 is, however, a light emitting diode (LED), but may also be two or more LEDs or an array of LEDs.
  • LED light emitting diode
  • each light unit 2 may include optical elements associated with the point light sources 3 and intended to contribute to forming a desired light distribution.
  • optical elements include, but are not limited to, e.g. reflectors, collimators.
  • a diffusor may be provided on the exit side of the optical elements, i.e. in front of the point light sources 3.
  • the output light of the lighting device is then formed by the optical elements and the diffusor in combination.
  • the diffuser has the function of slightly spreading the light, to at least partially mask the individual light sources while interfering little or not interfering at all with the light distribution.
  • the optical elements are fixed to the light source 3, while the diffuser is fixed to the bearing device 5 or if present to a housing of the lighting device 2.
  • Preferred diffusors should have a low diffusion factor, hence e.g. a 5 degrees FWHM diffuser would be suitable.
  • the contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b is made as large as possible, as a large contact surface provides for a good thermal interface.
  • the bearing device 5, 5a, 5b may furthermore be forming a second heat spreading device and/or a heatsink and/or it may form a housing enclosing the lighting device at least partially.
  • the bearing device 5 may also be constructed of one of more extra parts, i.e. of more than one part, which may function as housing and/or heatsink.
  • the housing may be provided as a separate element (not shown).
  • each first heat spreading device 4 is provided with two parts in the form of end sections 41, 42 each having a circular cross section.
  • the end sections 41, 42 are connected by a middle section 43 forming a cut-out in the first heat spreading device, in which cut-out the point light sources 3 a, 3b are mounted.
  • the two end sections 41, 42 each are cylindrical in shape.
  • Providing a first heat spreading device 4 with such a middle section 43 places the light emitting surface of the point light source 3 closer to the axis of the end sections 41, 42 of the first heat spreading device 4, which in turn reduces the movement of the light emitting surface when rotating the light unit 2.
  • the cut-out provided in the middle section 43 may in principle have any suitable shape.
  • Each first heat spreading device 4 of the nine light units 2 is arranged in the bearing device 5, 5a, 5b in such a way that the nine light units 2 are rotatable with respect to the bearing device 5, 5a, 5b and each around an axis of rotation extending through the respective centre of rotation of the end sections 41, 42 of the first heat spreading device 4, and thus around the centre of rotation of the end sections 41, 42 of the first heat spreading device 4..
  • One way of obtaining this is when the first heat spreading device 4 of each of the light units 2 is arranged in said bearing device 5, 5a, 5b in such a way that the first heat spreading device 4 forms an axle and the bearing device 5, 5a, 5b forms an axle-box.
  • the bearing device 5 is provided with receiving means 9 (Fig. 3) having a shape complementary to that of the parts of each first heat spreading device 4 having a circular cross section, i.e. the cylindrical end parts 41, 42. That is, the receiving means 9 likewise have a circular cross section.
  • the bearing device 5a, 5b comprises receiving means in the form of cylindrical through bores 9a, 9b.
  • bearing device 5, 5a, 5b is provided with a middle section comprising a shape complementary to that of the middle section 43, such as to provide a large contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b.
  • the receiving means 9, 9a, 9b may alternatively be provided as e.g. cylindrical recesses or bores.
  • the first heat spreading device 4 may be provided with another number of parts having a circular cross section than two.
  • the first heat spreading device may be provided with just one part having a circular cross section, particularly in that it may be provided with a circular cross section througout its extension.
  • the middle section of the bearing device 5 may in principle be omitted.
  • the part or parts of the heat spreading device having a circular cross-section e.g. the end sections 41 and 42 as described above, need not be provided with a fully circular cross section, but may just as well be provided with a partially circular cross section.
  • Such a partially circular cross section may for instance have the shape of a circle with one or more cut-off parts and/or with one or more cut-outs.
  • the nine light units may be mechanically connected with each other by means of a connecting means in the form of a connecting rod 6 or bar.
  • the connecting rod 6 is movable in the direction illustrated by the double arrow X in Figs 1 and 3. Thereby all of the light units 2 are rotated simultanously.
  • the connecting rod may in an additional embodiment be variable in size in its length direction, i.e. in the direction illustrated by the double arrow X, in a linear or non-linear manner.
  • the connecting rod 6 and each first heat spreading device 4 are connected by means of an intermediate device in the form of a pin 7.
  • the pin 7 is inserted with one end into a complementary hole 13 in each first heat spreading device 4, the hole 13 being excentrically arranged in each first heat spreading device 4.
  • the opposite end of the pin 7 is inserted into a hole (not shown) in the connecting rod.
  • each first heat spreading device 4 and the connecting means may in principle be achieved in any feasible way, such as by means of an adhesive, by means of magnetism or by means of any other feasible type of intermediate device.
  • the intermediate device and the first heat spreading device are one integral element.
  • the lighting device 1 shown in Fig. 1 comprises a thermal interface material 8 arranged between the first heat spreading device 4 and the bearing device 5a, 5b for improved heat spreading properties.
  • the thermal interface material 8 may be any suitable material having sufficient thermal conductivity, examples being a carbon film or a copper film.
  • a lubricant may be provided between the first heat spreading device 4 and the bearing device 5, 5a, 5b.
  • the advantage of such a lubricant is a smoother aiming by having lubrification and a lower thermal resistance.
  • the lubricant may in principle be any suitable lubricating material having sufficient thermal conductivity and stability, one example being a copper grease.
  • the lubricant and the thermal interface material 8 may be one and the same material. It is noted, however, that the lubricant and the thermal interface material 8 are purely optional.
  • the thermal interface material 8 is provided at the whole contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b for optimum heat spreading properties.
  • the thermal interface material may be provided at only a part of the contact surface between the first heat spreading device 4 and the bearing device 5, 5 a, 5b.
  • the lubricant if present, may be provided at the whole contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b, or alternatively at only a part of the contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b.
  • the lighting device 1 may be provided with an additional axis of rotation such as to enable aiming light in all possible directions. This may be achieved e.g. by connecting the bearing device 5, 5a, 5b and each first heat spreading device 4 in a manner as a cross joint or a cardan joint.
  • a separate housing it may be achieved by mounting the lighting device 1 as shown in the figures in the housing such as to be rotatable or tiltable with respect to the housing. This may be done in any suitable way, naturally including an axle/axle-box connection or a cross joint connection or a cardan joint connection.
  • the rotation of the light units may be manually or automatically (e.g. by a driving means such as an electromotor) actuated.
  • Figs. 4 to 6 show a second embodiment of a lighting device according to the invention.
  • the lighting device 10 comprises a bearing device 50 and an array of four times five light units 20.
  • Each of the thus totally twenty light units 20 comprises a first heat spreading device 40 and a point light source 30 mounted on the first heat spreading device 40.
  • the number of light units shown in the figures is merely one example, and in principle the lighting device may comprise any feasible number of light units, including just one light unit, arranged in any feasible number of rows and/or coloumns.
  • the number of point light sources 30 in each light unit may be any feasible number.
  • the point light source 30 may in principle be any feasible type of point light source, such as e.g. a light source with a pin hole arranged in front thereof, or an array of point light sources.
  • a linear light source such as e.g. a linear Chip-On-Board LED, may be used.
  • the at least one point light source 30 is, however, a light emitting diode (LED), but may also be two or more LEDs or an array of LEDs.
  • each light unit 20 may include optical elements associated with the point light sources 30 and intended to contribute to forming a desired light distribution.
  • Such optical elements include, but are not limited to, e.g. reflectors, collimators and diffusors.
  • Preferred diffusors should have a low diffusion factor, hence e.g. a 5 degrees FWHM diffuser would be suitable.
  • the diffusor is preferably placed in front of the point light sources such as to mask the individual point light sources.
  • a diffusor may be provided on the exit side of the optical elements, i.e. in front of the point light sources 30.
  • the output light of the lighting device is then formed by the optical elements and the diffusor in combination.
  • the diffuser has the function of slightly spreading the light, to at least partially mask the individual light sources while interfering little or not interfering at all with the light distribution.
  • the optical elements are fixed to the light source 30, while the diffuser is fixed to the bearing device 50 or if present to a housing of the lighting device.
  • the contact surface between the first heat spreading device 40 and the bearing device 50 is made as large as possible, as a large contact surface provides for a good thermal interface.
  • an air gap may be provided between the first heat spreading device 40 and the bearing device 50. If such an air gap is present it should preferably be made as small as possible, as a small air gap provides for a good thermal interface.
  • the bearing device 50 may furthermore be forming a second heat spreading device and/or a heatsink and/or it may form a housing enclosing the lighting device at least partially.
  • the bearing device 50 may also be construed of one of more extra parts, i.e. of more than one part, which may function as housing and/or heatsink.
  • the housing may be provided as a separate element (not shown).
  • each first heat spreading device 40 is provided with a part in the form of a spherical section 410 having a circular cross section and a centre of rotation and a middle section 430 forming a cut-out in the first heat spreading device 40.
  • the point light source 30 is mounted in the cut-out formed by the middle section 430.
  • Providing the first heat spreading device 40 with such a middle section 430 places the light emitting surface of the point light source 30 closer to the center of the spherical section 410 of the first heat spreading device 40, which in turn reduces the movement of the light emitting surface when rotating the light unit 20.
  • the cut-out in the middle section 430 may in principle have any suitable shape.
  • the part of the heat spreading device having a circular cross-section e.g. the spherical section 410 as described above, need not be provided with a fully circular cross section, but may just as well be provided with a partially circular cross section.
  • a partially circular cross section may for instance have the shape of a circle with one or more cut-off parts and/or with one or more cut-outs.
  • Each first heat spreading device 40 of the twenty light units 20 is arranged in the bearing device 50 in such a way that the twenty light units 20 are rotatable with respect to the bearing device 50 separately and each around the centre of rotation of the spherical section 410 of the first heat spreading device 40.
  • One way of obtaining this is when the first heat spreading device 40 of each of the light units 20 is arranged in said bearing device 50 in such a way that the first heat spreading device 40 forms an axle and the bearing device 50 forms an axle-box.
  • the bearing device 50 is provided with receiving means 90 (Fig. 4 and 5) having a shape complementary to that of the part of each first heat spreading device 40 having a circular cross section, i.e. the spherical section 410. That is, the receiving means 90 likewise have a circular cross section and a spherical shape.
  • the bearing device 50 comprises receiving means 90 in the form of through bores with spherical walls.
  • the receiving means 90 may alternatively be provided as e.g. spherical recesses or bores with spherical walls.
  • the first heat spreading device 40 may be provided with another number of sections having a circular cross section than one.
  • the twenty light units are mechanically connected with each other by means of a connecting means in the form of a connecting plate 60.
  • the connecting plate 60 is movable in any direction within the plane in which it extends, e.g. in the two directions illustrated by the double arrows X and Y in Figs 4 and 6. Thereby all of the light units 20 are rotated simultanously.
  • the connecting plate may in an additional embodiment be variable in its length and/or its width direction, i.e. in the directions illustrated by the double arrows X and Y, in a linear or non-linear manner.
  • the connecting plate 60 may be variable in a diagonal direction, such as in a direction in an angle of e.g. 30°, 45° or 50° with respect to either one of the width and length directions as illustrated by the double arrows X and Y, in a linear or non-linear manner.
  • each first heat spreading device 40 are connected by means of an intermediate device in the form of a pin 70.
  • the pin 70 is inserted with one end into a complementary hole (not shown) in each first heat spreading device 40.
  • the opposite end of the pin 70 is inserted into a hole 130 in the connecting plate 60.
  • the mechanical connection between each first heat spreading device 40 and the connecting means may in principle be achieved in any feasible way, such as by means of an adhesive, by means of magnetism or by means of any other feasible type of intermediate device.
  • the intermediate device and the first heat spreading device are one integral element.
  • the lighting device 10 shown in Figs. 4 to 6 may comprise a thermal interface material (not shown) arranged between the first heat spreading device 40 and the bearing device 50 for improved heat spreading properties.
  • the thermal interface material may be any suitable material having sufficient thermal conductivity, examples being a carbon film or a copper film.
  • a lubricant may be provided between the first heat spreading device 40 and the bearing device 50.
  • the advantage of such a lubricant is a smoother aiming by having lubrification and a lower thermal resistance.
  • the lubricant may in principle be any suitable lubricating material having sufficient thermal conductivity and thermal stability, one example being a copper grease.
  • the lubricant and the thermal interface material may be one and the same material. It is noted, however, that the lubricant and the thermal interface material are purely optional.
  • the thermal interface material may be provided at the whole contact surface between the first heat spreading device 40 and the bearing device 50 for optimum heat spreading properties. Alternatively, the thermal interface material may be provided at only a part of the contact surface between the first heat spreading device 40 and the bearing device 50. Likewise, the lubricant, if present, may be provided at the whole contact surface between the first heat spreading device 40 and the bearing device 50, or alternatively at only a part of the contact surface between the first heat spreading device 40 and the bearing device 50.
  • the lighting device 10 shown in Figs. 4 to 6 comprises a clamping device in the form of a clamping plate 14 arranged such as to retain the light units 20 and the bearing device 50 mutually connected.
  • the clamping plate 14 is provided with cut-outs having a spherical shape complementary to that of the first heat spreading devices.
  • the clamping plate 14 and the bearing device 50 are arranged in contact with each other and clamping the light units 20.
  • the clamping plate 14 may form a part of the bearing device 50, and/or it may be forming the thermal interface material.
  • the lighting device 10 may be provided with an additional axis of rotation such as to enable a larger angle of rotation of the light units 20.
  • the generally spherical shape of the first heat spreading device 40 and the bearing device 50 of the lighting device 10 enables aiming light in all directions.
  • the angle of rotation is limited to from around minus 45° to around plus 45° relative to a neutral starting position.
  • Providing an additional axis of rotation enables an angle of rotation of up to 360° in the direction of the additional axis of rotation, while maintaining the angle of rotation of +/-45° in other directions.
  • this may be achieved by mounting the lighting device 10 as shown in the figures in the housing such as to be rotatable or tiltable with respect to the housing.
  • the housing can be rotatable or tiltable relative to the surroundings, while having a fixed connection between the lighting device and the housing.
  • Fig. 7 shows an alternative embodiment of a lighting device 1 according to the invention and as shown in Figs. 1 and 3.
  • each first heat spreading device 4 is adapted for providing the electrical connection of the two point light sources 3 a, 3b of the respective light units 2.
  • the first heat spreading device 4 of each of the nine light units 2 is made of an electrically conductive material.
  • any number of point light sources may be present in each light unit.
  • any number of light units may in principle be present.
  • the number of point light sources and light units shown in Fig. 7 is purely intended as an example. The same considerations regarding the number of point light sources and light units apply to the embodiment shown in Fig. 8.
  • the first heat spreading device 4 of the light unit 2 is adapted for electrical connection with the first heat spreading device 4' of the adjacent light unit 2' by means of electrical connection means 15.
  • the electrical connection means 15 may in one embodiment simply be the bearing device 5, which in this case is made of an electrically conductive material.
  • the first heat spreading device 4 of the light unit 2 is adapted for electrical connection with an electrical connecting means in the form of a positive terminal 12 for conneting the lighting device 1 to a power supply.
  • the first heat spreading device 4" of the light unit 2" is adapted for electrical connection with an electrical connecting means in the form of a negative terminal 11 for connecting the lighting device 1 to a power supply.
  • the first heat spreading device 4 of each light unit 2 is provided with two parts, one for each point light source 3 a, 3b present.
  • the two parts are separated by means of an electrical insulator 16, which may be an air gap or an insulating material.
  • the two parts of the first heat spreading device 4 are connected by means of an electrical connection means bridging the insulator 16.
  • the elctrical insulator 16 may be omitted.
  • first heat spreading devices 4 and 4" may be adapted for direct electrical connection with a power supply, and likewise any one of the first heat spreading devices may be adapted for direct electrical connection with one or more adjacent first heat spreading devices.
  • Fig. 8 shows an alternative embodiment of a lighting device 10 according to the invention and as shown in Figs. 4 to 6.
  • each first heat spreading device 40 is adapted for providing the electrical connection of the point light sources 30 of the respective light units 20.
  • the first heat spreading device 40 of each light unit 20 is made of an electrically conductive material. In Fig. 8, only one light unit 20 of the lighting device 10 is shown.
  • the first heat spreading device 40 of the light unit 20 shown in Fig. 8 is adapted for electrical connection with an electrical connecting means 150 leading to a positive terminal 120 for conneting the lighting device 10 to a power supply.
  • the first heat spreading device 40 of the light unit 20 is adapted for electrical connection with another electrical connection means 150' leading through the pin 70 to a negative terminal 110 for connecting the lighting device 10 to a power supply.
  • the pin 70 is electrically insulated from the first heat spreading device 40 by means of an insulator 160.
  • connection means 150 " may be an isolated cable, in which case the insulator 160 between the pin 70 and the first heat spreading device 40 may be omitted.
  • the electrical connecting means 150 and 150' may lead to first heat spreading devices (not shown in Fig. 8) of adjacent light units (not shown in Fig. 8) of an array of light units such as that of e.g. the lighting device 10 of Fig. 4 to 6.
  • the electrical connection means 150 may in one embodiment simply be the bearing device 50, which in this case is made of an electrically conductive material.
  • the electrical connection means 150 may in one embodiment simply be the bearing device 50, which in this case is made of an electrically conductive material.
  • the 150' may in one embodiment simply be the pin 70, which in this case is made of an electrically conductive material.
  • first heat spreading device 40 may be adapted for direct electrical connection with a power supply, and/or for direct electrical connection with one or more adjacent first heat spreading devices.

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Abstract

A lighting device (1, 10) comprises a bearing device (5, 50) and one or more light units (2, 20), each of said one or more light units comprising a first heat spreading device (4, 40) and at least one point light source (3, 30) mounted on said first heat spreading device. The first heat spreading device (4, 40) comprises at least one part (41, 42, 410) having an at least partially circular cross section and a centre of rotation, and said first heat spreading device (4, 40) of each of said one or more light units (2, 20) is arranged in said bearing device (5, 50) in such a way that each of said one or more light units is rotatable with respect to said bearing device around said centre of rotation of said at least one part of said first heat spreading device.

Description

LIGHTING DEVICE COMPRISING A BEARING DEVICE
FIELD OF THE INVENTION
The invention relates to a lighting device comprising a bearing device and one or more light units, each of the one or more light units comprising a first heat spreading device and at least one point light source mounted on the first heat spreading device.
BACKGROUND OF THE INVENTION
Lighting devices of the above-mentioned type are widely used for lighting applications, in which a highly controlled and customizable light distribution is desired. Such applications include particularly spotlights, tiltable spots and spots that require an adjustable beam angle. Such lighting devices are suitable for both professional applications and consumer applications.
US 2009/0323330 Al describes a lighting device, in which each LED of the lighting device is provided with an associated optical element, which is adjustable. The associated optical element, which is adjustable, is preferably a reflector. The LEDs are mounted on a circuit board. The associated optical elements are mounted adjacent to each LED. The reflectors are individually adjustable e.g. by means of a setscrew. Finally, the assembly of circuit board, LEDs and associated optical elements are arranged in a housing.
Likewise, ligthing devices made tiltable as a whole in conjuction with their housing are known.
However, the prior art lighting devices have at least two disadvantages: at least when such lighting devices are adjusted, the LED and its associated optics, or at least the adjustable optical element, protrudes from the surface of the housing, which is not preferred for aesthetical reasons. Adjustable lighting devices which are adjusted within a housing and remain completely behind the surface area of the housing usually illuminate the inside of their own housing, resulting in a disturbed light distribution, a low optical efficiency and sometimes also causing glare. When lighting devices including a heatsink are tilted, this usually means a relatively large volume has to move. When lighting devices are tilted without their heatsink, the thermal resistance is relatively high. SUMMARY OF THE INVENTION
It is an object of the present invention to overcome these problems, and to provide a lighting device having well functioning heat spreading properties.
According to a first aspect of the invention, this and other objects are achieved with a lighting device as described initially and in which the first heat spreading device comprises at least one part having an at least partially circular cross section and a centre of rotation, and the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that each of the one or more light units is rotatable with respect to the bearing device around the centre of rotation of the at least one part of the first heat spreading device.
With such a lighting device it is ensured that the light unit and thereby the point light source remains behind the surface without disturbing the light distribution when tilting the light unit or light units. Also, a system with relatively small dimensions is obtained. Furthermore such a lighting device has been shown to have very good heat spreading properties, thus ensuring that the lighting device is not overheating during use.
Hence, lighting devices according to the invention may in particular be used for tiltable spots and for spots that require an adjustable beam angle and/or light distribution. Furthermore, lighting devices according to the invention are particularly advantageous when used in recessed spots and lighting systems where movement of the housing is not preferred and where a limited height is preferred.
In an embodiment, the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that the first heat spreading device forms an axle and the bearing device forms an axle-box.
Thereby the interface between the first heat spreading device and the bearing device functions as a mechanical bearing and a thermal interface at the same time, which provides for a particularly simple construction of the lighting device.
In an embodiment, the lighting device comprises two or more light units, and the first heat spreading device of each of the two or more light units are connected in such a way that the two or more light units are rotatable simultaneously with respect to the bearing device and each around the centre of rotation of the at least one part of the first heat spreading device.
Thereby all the light units of the lighting device may be rotated in one and the same movement. This ensures a particularly simple adjustment of the lighting device and thereby of the light distribution. In an embodiment, the at least one part of the first heat spreading device comprises an at least partially circular cross section and at least one axis of rotation extending through the centre of rotation, and the first heat spreading device of each of the one or more light units is arranged in the bearing device in such a way that each of the one or more light units is rotatable with respect to the bearing device around the at least one axis of rotation of the part of the first heat spreading device. Thereby a lighting device is provided having a more robust construction.
In an embodiment, the connection is provided by means of a mechanical connecting means, such a connecting rod or a connecting plate, which ensures a very simple way of establishing the connection.
In a further embodiment, the mechanical connecting means has a variable size in at least one direction. By providing the possibility of varying the size of the connecting means, in principle in any possible direction, but primarily in one or more of the width, length and a diagonal direction, further possibilities for varying the light distribution of the lighting device is provided. Thereby a large variety of light distributions, such as e.g. a narrow beam, a wide beam and a batwing-shaped beam, may be obtained. The size may be variable in a linear or non-linear manner.
In an embodiment, each first heat spreading device is connected to the connecting means by means of an intermediate device, such as at least one pin, thereby providing a particularly simple and robust connection between the connecting means and the first heat spreading device.
The intermediate device of each of the first heat spreading devices may be identical, e.g. all being cylindrical pins. Alternatively, each first heat spreading device may be connected to the connection means in such a way that the intermediate device is provided with its own path relative to the connection means. For example, the connection means may in this case be pins, each pin being provided with a specific form or shape, such as e.g. bent, curved, S-shaped, angled or the like. Thereby the light distribution may be changed in a way which is related to the angle of rotation, which may result in e.g. a small beam or an asymmetric beam. Alternatively, the connecting means may be a camshaft.
In an embodiment, the first heat spreading device is cylindrical and the bearing device comprises a receiving means, such as a cylindrical recess or bore, adapted for receiving the first heat spreading device. In an alternative embodiment, the first heat spreading device is spherical and the bearing device comprises a receiving means, such as a spherical recess or bore, adapted for receiving the first heat spreading device.
Thereby the lighting device is provided with a particularly simple relationship between the first heat spreading device and the bearing device, thus obtaining a particularly simple and durable construction.
In an embodiment, the bearing device forms a second heat spreading device and/or a heat sink, and/or the bearing device is made of more than one part. Thereby a lighting device is obtained which provides for more possibilities for providing the lighting device with different overall shapes.
In an embodiment, the lighting device furthermore comprises at least one thermal interface material arranged between the first heat spreading device and the bearing device, and/or at least one additional heat sink connected to the bearing device. Thereby a lighting device with improved heat dissipating properties is provided.
In an embodiment, the at least one light unit comprises optical elements such as e.g. a reflector, a collimator or a diffusor. Thereby a lighting device with improved light distribution is obtained.
In an embodiment, the bearing device forms the housing, which provides for a lighting device having a particularly simple construction.
In an embodiment, the first heat spreading device of each of the one or more light units is made of an electrically conductive material and is adapted for providing an electrical connection of the at least one or more light units to one or more other light units directly and/or by means of electrical connection means and/or to an electrical connecting means for connecting the lighting device to a power supply and/or to a power supply directly. With such a lighting device, a particularly simple, robust and cost effective electrical supply of the lighting device is obtained.
It is noted that the invention relates to all possible combinations of features recited in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.
In the drawings: Fig. 1 shows an exploded view of a first embodiment of a lighting device according to the invention comprising a plurality of light units.
Fig. 2 shows an exploded view of the first embodiment of a lighting device according to the invention comprising one light unit.
Fig. 3 shows a perspective view of the lighting device according to Fig. 1 in an assembled state.
Fig. 4 shows an exploded view of a second embodiment of a lighting device according to the invention comprising a plurality of light units.
Fig. 5 shows a cross sectional view of a row of light units of the lighting device according to Fig. 4.
Fig. 6 shows a perspective view of the lighting device according to Fig. 4 in an assembled state.
Fig. 7 shows a cross sectional view seen from below of the lighting device according to Fig. 1 in which the first heat spreading devices are adapted for providing an electrical connection of said light units.
Fig. 8 shows a cross sectional view of one of the light units of the lighting device according to Fig. 4 in which the first heat spreading device is adapted for providing an electrical connection of the light unit.
DETAILED DESCRIPTION
In the following two different embodiments of a lighting device according to the invention is described. In the description, elements having the same or analogous function carry the same reference numeral to which a zero has been added, examples being e.g. 1 and 10 or 2 and 20.
Figs. 1 to 3 show a first embodiment of a lighting device according to the invention. The lighting device 1 shown in Figs. 1 and 3 comprises a bearing device 5, 5a, 5b and nine light units 2. Each of the nine light units 2 comprises a first heat spreading device 4 and two point light sources 3a, 3b mounted on the first heat spreading device 4. Fig. 2 shows a version of the lighting device 1 comprising just one light unit 2, but otherwise having the same construction as the lighting device 1 shown in Figs. 1 and 3.
Obviously the number of light units shown in the figures is merely one example, and in principle the lighting device may comprise any feasible or desirable number of light units, including just one light unit. Likewise, the number of point light sources 3 (Fig. 3) in each light unit may be any feasible or desirable number. Also, the point light source 3 may in principle be any feasible type of point light source, such as e.g. a light source with a pin hole arranged in front thereof, or an array of point light sources. Alternatively, a linear light source, such as e.g. a linear Chip-On-Board LED, may be used. In the embodiments shown in the drawings the at least one point light source 3 is, however, a light emitting diode (LED), but may also be two or more LEDs or an array of LEDs.
Although not specifically shown on the drawings, it is noted that each light unit 2 may include optical elements associated with the point light sources 3 and intended to contribute to forming a desired light distribution. Such optical elements include, but are not limited to, e.g. reflectors, collimators.
Furthermore, in addition to the optical elements, a diffusor may be provided on the exit side of the optical elements, i.e. in front of the point light sources 3. The output light of the lighting device is then formed by the optical elements and the diffusor in combination. The diffuser has the function of slightly spreading the light, to at least partially mask the individual light sources while interfering little or not interfering at all with the light distribution. The optical elements are fixed to the light source 3, while the diffuser is fixed to the bearing device 5 or if present to a housing of the lighting device 2. Preferred diffusors should have a low diffusion factor, hence e.g. a 5 degrees FWHM diffuser would be suitable.
Preferably, the contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b is made as large as possible, as a large contact surface provides for a good thermal interface.
In alternative embodiments the bearing device 5, 5a, 5b may furthermore be forming a second heat spreading device and/or a heatsink and/or it may form a housing enclosing the lighting device at least partially. In a further alternative embodiment the bearing device 5 may also be constructed of one of more extra parts, i.e. of more than one part, which may function as housing and/or heatsink. Alternatively, the housing may be provided as a separate element (not shown).
In the embodiment shown in Figs. 1 to 3, each first heat spreading device 4 is provided with two parts in the form of end sections 41, 42 each having a circular cross section. The end sections 41, 42 are connected by a middle section 43 forming a cut-out in the first heat spreading device, in which cut-out the point light sources 3 a, 3b are mounted. As may be seen, the two end sections 41, 42 each are cylindrical in shape. Providing a first heat spreading device 4 with such a middle section 43 places the light emitting surface of the point light source 3 closer to the axis of the end sections 41, 42 of the first heat spreading device 4, which in turn reduces the movement of the light emitting surface when rotating the light unit 2. It is noted that the cut-out provided in the middle section 43 may in principle have any suitable shape.
Each first heat spreading device 4 of the nine light units 2 is arranged in the bearing device 5, 5a, 5b in such a way that the nine light units 2 are rotatable with respect to the bearing device 5, 5a, 5b and each around an axis of rotation extending through the respective centre of rotation of the end sections 41, 42 of the first heat spreading device 4, and thus around the centre of rotation of the end sections 41, 42 of the first heat spreading device 4.. One way of obtaining this is when the first heat spreading device 4 of each of the light units 2 is arranged in said bearing device 5, 5a, 5b in such a way that the first heat spreading device 4 forms an axle and the bearing device 5, 5a, 5b forms an axle-box.
As shown in Figs. 1 to 3, this is obtained in that the bearing device 5 is provided with receiving means 9 (Fig. 3) having a shape complementary to that of the parts of each first heat spreading device 4 having a circular cross section, i.e. the cylindrical end parts 41, 42. That is, the receiving means 9 likewise have a circular cross section.
Particularly, as shown on Fig. 1, the bearing device 5a, 5b comprises receiving means in the form of cylindrical through bores 9a, 9b.
Furthermore the bearing device 5, 5a, 5b is provided with a middle section comprising a shape complementary to that of the middle section 43, such as to provide a large contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b.
It is noted that the receiving means 9, 9a, 9b may alternatively be provided as e.g. cylindrical recesses or bores. Likewise the first heat spreading device 4 may be provided with another number of parts having a circular cross section than two. E.g., the first heat spreading device may be provided with just one part having a circular cross section, particularly in that it may be provided with a circular cross section througout its extension. Also, the middle section of the bearing device 5 may in principle be omitted. Likewise, the part or parts of the heat spreading device having a circular cross-section, e.g. the end sections 41 and 42 as described above, need not be provided with a fully circular cross section, but may just as well be provided with a partially circular cross section. Such a partially circular cross section may for instance have the shape of a circle with one or more cut-off parts and/or with one or more cut-outs. As shown schematically in Fig. 3, the nine light units may be mechanically connected with each other by means of a connecting means in the form of a connecting rod 6 or bar. The connecting rod 6 is movable in the direction illustrated by the double arrow X in Figs 1 and 3. Thereby all of the light units 2 are rotated simultanously. The connecting rod may in an additional embodiment be variable in size in its length direction, i.e. in the direction illustrated by the double arrow X, in a linear or non-linear manner.
The connecting rod 6 and each first heat spreading device 4 are connected by means of an intermediate device in the form of a pin 7. The pin 7 is inserted with one end into a complementary hole 13 in each first heat spreading device 4, the hole 13 being excentrically arranged in each first heat spreading device 4. The opposite end of the pin 7 is inserted into a hole (not shown) in the connecting rod.
It is noted that the mechanical connection between each first heat spreading device 4 and the connecting means may in principle be achieved in any feasible way, such as by means of an adhesive, by means of magnetism or by means of any other feasible type of intermediate device. In an alternative embodiment the intermediate device and the first heat spreading device are one integral element.
Furthermore, the lighting device 1 shown in Fig. 1 comprises a thermal interface material 8 arranged between the first heat spreading device 4 and the bearing device 5a, 5b for improved heat spreading properties. The thermal interface material 8 may be any suitable material having sufficient thermal conductivity, examples being a carbon film or a copper film.
Alternatively or in addition thereto, a lubricant may be provided between the first heat spreading device 4 and the bearing device 5, 5a, 5b. The advantage of such a lubricant is a smoother aiming by having lubrification and a lower thermal resistance. The lubricant may in principle be any suitable lubricating material having sufficient thermal conductivity and stability, one example being a copper grease. In one embodiment, the lubricant and the thermal interface material 8 may be one and the same material. It is noted, however, that the lubricant and the thermal interface material 8 are purely optional.
As shown in Fig. 1, the thermal interface material 8 is provided at the whole contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b for optimum heat spreading properties. Alternatively, the thermal interface material may be provided at only a part of the contact surface between the first heat spreading device 4 and the bearing device 5, 5 a, 5b. Likewise, the lubricant, if present, may be provided at the whole contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b, or alternatively at only a part of the contact surface between the first heat spreading device 4 and the bearing device 5, 5a, 5b.
Also, the lighting device 1 according to the invention may be provided with an additional axis of rotation such as to enable aiming light in all possible directions. This may be achieved e.g. by connecting the bearing device 5, 5a, 5b and each first heat spreading device 4 in a manner as a cross joint or a cardan joint. Alternatively, when a separate housing is provided, it may be achieved by mounting the lighting device 1 as shown in the figures in the housing such as to be rotatable or tiltable with respect to the housing. This may be done in any suitable way, naturally including an axle/axle-box connection or a cross joint connection or a cardan joint connection.
Irrespective of the embodiment, the rotation of the light units, whether a connecting means is present or not, may be manually or automatically (e.g. by a driving means such as an electromotor) actuated.
Other alternatives applicable irrespective of the embodiments include the following: providing the additional axis of rotation by making the whole lighting device including housing rotatable or tiltable, omitting the connecting means and/or the intermediate means, such that the light units may be rotated individually, and/or actuating the rotation of the individual light units by means of an adjustment means such as e.g. a set screw.
Figs. 4 to 6 show a second embodiment of a lighting device according to the invention. The lighting device 10 comprises a bearing device 50 and an array of four times five light units 20. Each of the thus totally twenty light units 20 comprises a first heat spreading device 40 and a point light source 30 mounted on the first heat spreading device 40.
Obviously the number of light units shown in the figures is merely one example, and in principle the lighting device may comprise any feasible number of light units, including just one light unit, arranged in any feasible number of rows and/or coloumns.
Likewise, the number of point light sources 30 in each light unit may be any feasible number. The point light source 30 may in principle be any feasible type of point light source, such as e.g. a light source with a pin hole arranged in front thereof, or an array of point light sources. Alternatively, a linear light source, such as e.g. a linear Chip-On-Board LED, may be used. In the embodiments shown in the drawings the at least one point light source 30 is, however, a light emitting diode (LED), but may also be two or more LEDs or an array of LEDs. Although not specifically shown on the drawings, it is noted that each light unit 20 may include optical elements associated with the point light sources 30 and intended to contribute to forming a desired light distribution. Such optical elements include, but are not limited to, e.g. reflectors, collimators and diffusors. Preferred diffusors should have a low diffusion factor, hence e.g. a 5 degrees FWHM diffuser would be suitable. When present the diffusor is preferably placed in front of the point light sources such as to mask the individual point light sources.
Furthermore, in addition to the optical elements, a diffusor may be provided on the exit side of the optical elements, i.e. in front of the point light sources 30. The output light of the lighting device is then formed by the optical elements and the diffusor in combination. The diffuser has the function of slightly spreading the light, to at least partially mask the individual light sources while interfering little or not interfering at all with the light distribution. The optical elements are fixed to the light source 30, while the diffuser is fixed to the bearing device 50 or if present to a housing of the lighting device.
Preferably, the contact surface between the first heat spreading device 40 and the bearing device 50 is made as large as possible, as a large contact surface provides for a good thermal interface. Also, an air gap may be provided between the first heat spreading device 40 and the bearing device 50. If such an air gap is present it should preferably be made as small as possible, as a small air gap provides for a good thermal interface.
In alternative embodiments the bearing device 50 may furthermore be forming a second heat spreading device and/or a heatsink and/or it may form a housing enclosing the lighting device at least partially. In a further alternative embodiment the bearing device 50 may also be construed of one of more extra parts, i.e. of more than one part, which may function as housing and/or heatsink. Alternatively, the housing may be provided as a separate element (not shown).
In the embodiment shown in Figs. 4 to 6, each first heat spreading device 40 is provided with a part in the form of a spherical section 410 having a circular cross section and a centre of rotation and a middle section 430 forming a cut-out in the first heat spreading device 40. The point light source 30 is mounted in the cut-out formed by the middle section 430. Providing the first heat spreading device 40 with such a middle section 430 places the light emitting surface of the point light source 30 closer to the center of the spherical section 410 of the first heat spreading device 40, which in turn reduces the movement of the light emitting surface when rotating the light unit 20. It is noted that the cut-out in the middle section 430 may in principle have any suitable shape. Likewise, the part of the heat spreading device having a circular cross-section, e.g. the spherical section 410 as described above, need not be provided with a fully circular cross section, but may just as well be provided with a partially circular cross section. Such a partially circular cross section may for instance have the shape of a circle with one or more cut-off parts and/or with one or more cut-outs.
Each first heat spreading device 40 of the twenty light units 20 is arranged in the bearing device 50 in such a way that the twenty light units 20 are rotatable with respect to the bearing device 50 separately and each around the centre of rotation of the spherical section 410 of the first heat spreading device 40. One way of obtaining this is when the first heat spreading device 40 of each of the light units 20 is arranged in said bearing device 50 in such a way that the first heat spreading device 40 forms an axle and the bearing device 50 forms an axle-box.
As shown in Figs. 4 to 6, this is obtained in that the bearing device 50 is provided with receiving means 90 (Fig. 4 and 5) having a shape complementary to that of the part of each first heat spreading device 40 having a circular cross section, i.e. the spherical section 410. That is, the receiving means 90 likewise have a circular cross section and a spherical shape. Particularly, as shown on Fig. 4, the bearing device 50 comprises receiving means 90 in the form of through bores with spherical walls.
It is noted that the receiving means 90 may alternatively be provided as e.g. spherical recesses or bores with spherical walls. Likewise the first heat spreading device 40 may be provided with another number of sections having a circular cross section than one.
As schematically shown in Fig. 6, the twenty light units are mechanically connected with each other by means of a connecting means in the form of a connecting plate 60. The connecting plate 60 is movable in any direction within the plane in which it extends, e.g. in the two directions illustrated by the double arrows X and Y in Figs 4 and 6. Thereby all of the light units 20 are rotated simultanously. The connecting plate may in an additional embodiment be variable in its length and/or its width direction, i.e. in the directions illustrated by the double arrows X and Y, in a linear or non-linear manner. Alternatively or in addition thereto, the connecting plate 60 may be variable in a diagonal direction, such as in a direction in an angle of e.g. 30°, 45° or 50° with respect to either one of the width and length directions as illustrated by the double arrows X and Y, in a linear or non-linear manner.
The connecting plate 60 and each first heat spreading device 40 are connected by means of an intermediate device in the form of a pin 70. The pin 70 is inserted with one end into a complementary hole (not shown) in each first heat spreading device 40. The opposite end of the pin 70 is inserted into a hole 130 in the connecting plate 60. It is noted that the mechanical connection between each first heat spreading device 40 and the connecting means may in principle be achieved in any feasible way, such as by means of an adhesive, by means of magnetism or by means of any other feasible type of intermediate device. In an alternative embodiment the intermediate device and the first heat spreading device are one integral element.
The lighting device 10 shown in Figs. 4 to 6 may comprise a thermal interface material (not shown) arranged between the first heat spreading device 40 and the bearing device 50 for improved heat spreading properties. The thermal interface material may be any suitable material having sufficient thermal conductivity, examples being a carbon film or a copper film.
Alternatively or in addition thereto, a lubricant may be provided between the first heat spreading device 40 and the bearing device 50. The advantage of such a lubricant is a smoother aiming by having lubrification and a lower thermal resistance. The lubricant may in principle be any suitable lubricating material having sufficient thermal conductivity and thermal stability, one example being a copper grease. In one embodiment, the lubricant and the thermal interface material may be one and the same material. It is noted, however, that the lubricant and the thermal interface material are purely optional.
The thermal interface material may be provided at the whole contact surface between the first heat spreading device 40 and the bearing device 50 for optimum heat spreading properties. Alternatively, the thermal interface material may be provided at only a part of the contact surface between the first heat spreading device 40 and the bearing device 50. Likewise, the lubricant, if present, may be provided at the whole contact surface between the first heat spreading device 40 and the bearing device 50, or alternatively at only a part of the contact surface between the first heat spreading device 40 and the bearing device 50.
Furthermore, the lighting device 10 shown in Figs. 4 to 6 comprises a clamping device in the form of a clamping plate 14 arranged such as to retain the light units 20 and the bearing device 50 mutually connected. To this end the clamping plate 14 is provided with cut-outs having a spherical shape complementary to that of the first heat spreading devices. In the assembled state of the lighting device 10 (Fig. 6), the clamping plate 14 and the bearing device 50 are arranged in contact with each other and clamping the light units 20. The clamping plate 14 may form a part of the bearing device 50, and/or it may be forming the thermal interface material.
Also, the lighting device 10 according to the invention may be provided with an additional axis of rotation such as to enable a larger angle of rotation of the light units 20. The generally spherical shape of the first heat spreading device 40 and the bearing device 50 of the lighting device 10 enables aiming light in all directions. However, the angle of rotation is limited to from around minus 45° to around plus 45° relative to a neutral starting position. Providing an additional axis of rotation enables an angle of rotation of up to 360° in the direction of the additional axis of rotation, while maintaining the angle of rotation of +/-45° in other directions. When a separate housing is provided, this may be achieved by mounting the lighting device 10 as shown in the figures in the housing such as to be rotatable or tiltable with respect to the housing. This may be done in any suitable way, naturally including an axle/axle-box connection and a cross joint or a cardan joint connection. Also the housing can be rotatable or tiltable relative to the surroundings, while having a fixed connection between the lighting device and the housing.
Fig. 7 shows an alternative embodiment of a lighting device 1 according to the invention and as shown in Figs. 1 and 3. In this alternative embodiment, each first heat spreading device 4 is adapted for providing the electrical connection of the two point light sources 3 a, 3b of the respective light units 2. The first heat spreading device 4 of each of the nine light units 2 is made of an electrically conductive material.
It is noted, that in principle any number of point light sources may be present in each light unit. Likewise any number of light units may in principle be present. Hence, the number of point light sources and light units shown in Fig. 7 is purely intended as an example. The same considerations regarding the number of point light sources and light units apply to the embodiment shown in Fig. 8.
By way of example, the first heat spreading device 4 of the light unit 2 is adapted for electrical connection with the first heat spreading device 4' of the adjacent light unit 2' by means of electrical connection means 15. The electrical connection means 15 may in one embodiment simply be the bearing device 5, which in this case is made of an electrically conductive material. Likewise, the first heat spreading device 4 of the light unit 2 is adapted for electrical connection with an electrical connecting means in the form of a positive terminal 12 for conneting the lighting device 1 to a power supply. In an analogous manner, the first heat spreading device 4" of the light unit 2" is adapted for electrical connection with an electrical connecting means in the form of a negative terminal 11 for connecting the lighting device 1 to a power supply.
As may be seen in Fig. 7, the first heat spreading device 4 of each light unit 2 is provided with two parts, one for each point light source 3 a, 3b present. The two parts are separated by means of an electrical insulator 16, which may be an air gap or an insulating material. The two parts of the first heat spreading device 4 are connected by means of an electrical connection means bridging the insulator 16. In an alternative embodiment the elctrical insulator 16 may be omitted.
Alternatively the first heat spreading devices 4 and 4" may be adapted for direct electrical connection with a power supply, and likewise any one of the first heat spreading devices may be adapted for direct electrical connection with one or more adjacent first heat spreading devices.
Fig. 8 shows an alternative embodiment of a lighting device 10 according to the invention and as shown in Figs. 4 to 6. In this alternative embodiment, each first heat spreading device 40 is adapted for providing the electrical connection of the point light sources 30 of the respective light units 20. The first heat spreading device 40 of each light unit 20 is made of an electrically conductive material. In Fig. 8, only one light unit 20 of the lighting device 10 is shown.
By way of example, the first heat spreading device 40 of the light unit 20 shown in Fig. 8 is adapted for electrical connection with an electrical connecting means 150 leading to a positive terminal 120 for conneting the lighting device 10 to a power supply.
Likewise, the first heat spreading device 40 of the light unit 20 is adapted for electrical connection with another electrical connection means 150' leading through the pin 70 to a negative terminal 110 for connecting the lighting device 10 to a power supply. The pin 70 is electrically insulated from the first heat spreading device 40 by means of an insulator 160.
The connection means 150" may be an isolated cable, in which case the insulator 160 between the pin 70 and the first heat spreading device 40 may be omitted.
Alternatively the electrical connecting means 150 and 150' may lead to first heat spreading devices (not shown in Fig. 8) of adjacent light units (not shown in Fig. 8) of an array of light units such as that of e.g. the lighting device 10 of Fig. 4 to 6. The electrical connection means 150 may in one embodiment simply be the bearing device 50, which in this case is made of an electrically conductive material. Likewise the electrical connection means
150' may in one embodiment simply be the pin 70, which in this case is made of an electrically conductive material.
Alternatively the first heat spreading device 40 may be adapted for direct electrical connection with a power supply, and/or for direct electrical connection with one or more adjacent first heat spreading devices. The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Claims

CLAIMS:
1. A lighting device (1, 10) comprising a bearing device (5, 5a, 5b, 50) and one or more light units (2, 20), each of said one or more light units comprising a first heat spreading device (4, 40) and at least one point light source (3, 30) mounted on said first heat spreading device, characterized in that:
said first heat spreading device (4, 40) comprises at least one part (41, 42, 410) having an at least partially circular cross section and a centre of rotation, and that
said first heat spreading device (4, 40) of each of said one or more light units (2, 20) is arranged in said bearing device (5, 50) in such a way that each of said one or more light units is rotatable with respect to said bearing device around said centre of rotation of said at least one part of said first heat spreading device.
2. A lighting device according to claim 1, characterized in that said first heat spreading device (4, 40) of each of said one or more light units (2, 20) is arranged in said bearing device (5, 5a, 5b, 50) in such a way that said first heat spreading device forms an axle and said bearing device forms an axle-box.
3. A lighting device according to claim 1 or 2, characterized in that it comprises two or more light units (2, 20), and that the first heat spreading device (4, 40) of each of the two or more light units (2, 20) are connected in such a way that said two or more light units are rotatable simultaneously with respect to said bearing device (5, 50) and each around said centre of rotation of said at least one part of said first heat spreading device.
4. A lighting device according to any one of the above claims, characterized in that said at least one part (41, 42, 410) of said first heat spreading device (4, 40) comprises an at least partially circular cross section and at least one axis of rotation extending through said centre of rotation, and that
said first heat spreading device (4, 40) of each of said one or more light units (2, 20) is arranged in said bearing device (5, 50) in such a way that each of said one or more light units is rotatable with respect to said bearing device around said at least one axis of rotation of said part of said first heat spreading device.
5. A lighting device according to claim 3 or 4, characterized in that said connection is provided by means of a mechanical connecting means (6, 60), such as a connecting rod or a connecting plate.
6. A lighting device according to claim 5, characterized in that said mechanical connecting means (6, 60) has a variable size in at least one direction.
7. A lighting device according to any one of claims 5-6, characterized in that each said first heat spreading device (4, 40) is connected to said connecting means (6, 60) by means of an intermediate device, such as at least one pin (7, 70).
8. A lighting device according to any one of the above claims, characterized in that the first heat spreading device (4) is cylindrical and in that said bearing device (5, 5a, 5b) comprises a receiving means (9; 9a, 9b), such as a cylindrical recess or bore, adapted for receiving said first heat spreading device.
9. A lighting device according to any one of claims 1-7, characterized in that the first heat spreading device (40) is spherical and in that said bearing device (50) comprises a receiving means (90), such as a spherical recess or bore, adapted for receiving said first heat spreading device.
10. A lighting device according to any one of the above claims, characterized in that said bearing device (5, 5a, 5b, 50) forms a second heat spreading device and/or a heat sink, and/or that said bearing device (5, 5a, 5b, 50) is made of more than one part.
11. A lighting device according to any one of the above claims, characterized in that it furthermore comprises at least one thermal interface material arranged between said first heat spreading device (4, 40) and said bearing device (5, 5a, 5b, 50), and/or at least one additional heat sink connected to said bearing device (5, 5a, 5b, 50).
12. A lighting device according to any one of the above claims, characterized in that said at least one point light source (3, 30) is at least one light emitting diode (LED) or an array of LEDs.
13. A lighting device according to any one of the above claims, characterized in that a lubricant is provided between said first heat spreading device (4, 40) and said bearing device (5, 5a, 5b, 50), and/or in that a diffusor is provided in front of said at least one point light source (3, 30), and/or in that it furthermore comprises at least one housing enclosing said lighting device (1, 10) at least partially.
14. A lighting device according to claim 13, characterized in that said bearing device (5, 5a, 5b, 50) forms said housing.
15. A lighting device according to any one of the above claims, characterized in that said first heat spreading device (4, 40) of each of said one or more light units (2, 20) is made of an electrically conductive material and is adapted for providing an electrical connection of said at least one or more light units (2, 20) to one or more other light units directly and/or by means of electrical connection means (15, 150) and/or to an electrical connecting means (11, 12, 110, 120) for connecting said lighting device (1, 10) to a power supply and/or to a power supply directly.
PCT/IB2013/054597 2012-06-05 2013-06-04 Lighting device comprising a bearing device WO2013182989A1 (en)

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US201261655534P 2012-06-05 2012-06-05
US61/655,534 2012-06-05

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Citations (6)

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Publication number Priority date Publication date Assignee Title
JP2002324405A (en) * 2001-04-26 2002-11-08 T O D Kk Led rotary lamp
DE102004023358B3 (en) * 2004-05-12 2006-04-06 Michael Smit Lighting arrangement for a stage comprises a first adjusting element interacting with lighting bodies and moving on a housing to simultaneously pivot the lighting bodies and a second adjusting element
US20070263388A1 (en) * 2006-05-12 2007-11-15 Industrial Technology Research Institute Illumination device of flexible lighting angle
US20090323330A1 (en) 2008-05-16 2009-12-31 Musco Corporation Method, system and apparatus for highly controlled light distribution from light fixture using multiple light sources (led's)
WO2010086213A1 (en) * 2009-01-28 2010-08-05 Osram Gesellschaft mit beschränkter Haftung Led-lamp mounting and method for operating an led-lamp
EP2428720A2 (en) * 2010-09-10 2012-03-14 Terence Woodgate Light fixture

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002324405A (en) * 2001-04-26 2002-11-08 T O D Kk Led rotary lamp
DE102004023358B3 (en) * 2004-05-12 2006-04-06 Michael Smit Lighting arrangement for a stage comprises a first adjusting element interacting with lighting bodies and moving on a housing to simultaneously pivot the lighting bodies and a second adjusting element
US20070263388A1 (en) * 2006-05-12 2007-11-15 Industrial Technology Research Institute Illumination device of flexible lighting angle
US20090323330A1 (en) 2008-05-16 2009-12-31 Musco Corporation Method, system and apparatus for highly controlled light distribution from light fixture using multiple light sources (led's)
WO2010086213A1 (en) * 2009-01-28 2010-08-05 Osram Gesellschaft mit beschränkter Haftung Led-lamp mounting and method for operating an led-lamp
EP2428720A2 (en) * 2010-09-10 2012-03-14 Terence Woodgate Light fixture

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