WO2009150574A1

WO2009150574A1 - Lamp unit and luminaire

Info

Publication number: WO2009150574A1
Application number: PCT/IB2009/052343
Authority: WO
Inventors: Michel C. J. M. Vissenberg; Anthonie H. Bergman; Tim Dekker
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2008-06-10
Filing date: 2009-06-03
Publication date: 2009-12-17
Also published as: TW201009237A

Abstract

The present invention relates to a lamp unit (10), comprising: a lamp base (12); at least one first light source (16, 26, 64) adapted to emit first light having a first wavelength spectrum; and at least one second light source (14, 38, 40, 62) adapted to emit second light having a second wavelength spectrum different from the first wavelength spectrum, wherein the lamp unit is arranged so as to emit the first light in at least one certain 5 direction and the second light in at least one other direction. The present invention also relates to aluminaire (74, 78) comprising at least one such lamp unit (10).

Description

Lamp unit and luminaire

FIELD OF THE INVENTION

The present invention relates to a lamp unit. The present invention also relates to a luminaire comprising at least one such lamp unit.

BACKGROUND OF THE INVENTION

A traditional lamp unit, such as an incandescent or filament lamp, is usually adapted to emit white light only. For emitting colored light, such a lamp may be provided with a color filter.

Philips NightGuide is an example of a lamp unit which is adapted to emit white light in a first direction as well as bluish white light in a second direction and yellowish white light in a third direction. To achieve this, the NightGuide lamp comprises a white light source and colored coatings for appropriately manipulating the white light. The NightGuide lamp is dedicated to automotive applications. A property of the NightGuide lamp is that color filters reduce the efficiency of the lamp. Another property is that the effect is static. To change the effect, the lamp has to be replaced.

Further, the patent document BE-1015507 discloses a light fitting for providing colored and white light in different directions. The light fitting comprises two or more white lights, of which at least one is dimmable and on one side a separate color filter is provided for each light and on the other side there are no (different) color filters. However, a drawback with such a light fitting is that one has to replace a conventional luminaire with this light fitting in order to have the colored and white light in different directions.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partly overcome at least one of the above mentioned problems and drawbacks, and to provide an improved solution for providing different light in different directions.

This and other objects that will be apparent from the following description are achieved by a lamp unit and a luminaire according to the appended independent claims. According to an aspect of the present invention, there is provided a lamp unit comprising: a lamp base; at least one first light source adapted to emit first light having a first wavelength spectrum; and at least one second light source adapted to emit second light having a second wavelength spectrum different from the first wavelength spectrum, wherein the lamp unit is arranged so as to emit the first light in at least one certain direction and the second light in at least one other direction.

Hence, the dual functionality of providing first and second light in different directions is placed in the lamp unit, rather than providing the dual functionality at the luminaire or light fitting level. In other words, the lamp unit itself (instead of the luminaire) is arranged such that during operation the first light is emitted in at least one certain direction and the second light is emitted in at least one other direction. This allows the lamp unit to be retrofitted in an existing luminaire or light fitting, so that first and second light in different directions beneficially can be provided without having to replace the complete luminaire. Further, separate light sources for emitting the first and second light beneficially allows for separate control of the first and second light.

Preferably, the first light is white light (wide(r) spectrum), whereas the second light is colored light (narrow(er) spectrum). Alternatively, the first light may also be colored light, but of a different color than the second light.

Also preferably, the lamp base is adapted to be fitted in a lamp socket, more preferably a standard type lamp socket. This allows the lamp unit to be retrofitted in an existing light fitting or luminaire having such a lamp socket. The standard type lamp socket may for instance be a traditional screw socket or a bayonet socket. In the former case, the lamp base is a traditional screw lamp base with suitable threads.

Determining the direction of the emitted light may be achieved by appropriately selecting at least one of primary optics of the light sources, orientation of the light sources, and secondary optics of the lamp unit, such that during operation the first (e.g. white) light is emitted in the at least one certain direction and the second (e.g. colored) light is emitted in the at least one other direction. Here, primary optics are adapted to manipulate light emitted directly from the light source and are usually incorporated in the light source package, whereas secondary optics usually are placed outside the light source package and are adapted to manipulate light from the light source that has already been manipulated by the primary optics. The manipulation may for instance include direction, re-direction, collimation, reflection, etc. Having the primary optics and/or orientation determining the direction of emitted light is beneficial since it allows for a straight forward and rather simple construction of the rest of the lamp unit without any specially designed secondary optics. On the other hand, having the secondary optics determining the direction of emitted light is advantageous in that more precise control of the direction of the emitted light is allowed.

In one embodiment, the at least one first light source comprises primary optics adapted to direct the first light in the at least one certain direction, and the at least one second light source comprises primary optics adapted to direct the second light in the at least one other direction. For instance, the at least one first light source may have primary optics for side-emission, whereas the at least one second light source has primary optics for top- emission, to create for instance white light that is aimed sideways and colored light that is aimed upwards, in relation to the lamp base.

In another embodiment, the light sources are directional light sources, wherein the at least one first light source is oriented so as to emit the first light in the at least one certain direction and the at least one second light source is oriented so as to emit the second light in the at least one other direction. Directional light sources are light sources adapted to emit light generally in a specific direction or having a limited output angle, for instance top- emitters, in contrast to omni-directional emitters. In an exemplary variant of this embodiment, the light sources are top-emitters, and the at least one first light source is oriented to aim white light to the left, whereas the at least one second light source is oriented to aim colored light to the right, in relation to the lamp base. In yet another embodiment, the lamp unit further comprises secondary optics adapted to direct or redirect the first light in the at least one certain direction and the second light in the at least one other direction. The secondary optics may for instance comprise total internal reflection (TIR) elements, and/or light guides with out-coupling facets.

Preferably, the (first and second) light sources of the present lamp unit are light emitting diodes (LEDs), though other light sources could be used. Benefits of LEDs include high efficiency, long useful life, etc. Also, an LED-based lamp unit allows for more precise control over the direction of the light, due to the small size of the LED light sources, as well as for dynamic control over the color and/or direction of the light.

Also preferably, the at least one certain direction and the at least one other direction are generally opposite or right-angled in relation to each other. Preferably, the at least one certain direction corresponds to functional or task light, e.g. white light directed towards the floor and/or a table from a ceiling lamp, whereas the at least one other direction corresponds to atmospheric or atmosphere providing light, e.g. colored light directed towards the ceiling (opposite the floor). The emission of the first light and the second light may overlap directionally, as long as the second light has at least one other direction compared to the first light.

The present lamp unit may further comprise a controller adapted to selectively control the at least one first light source and the at least one second light source. This beneficially allows for dynamic control of the emitted light, so that the lamp unit not necessarily have to be replaced should a different lighting effect be desired.

Settings (of the light sources) controlled by the controller may include, but is not limited to, at least one of on/off state, dim or intensity level, saturation, color temperature, and hue or color. Also, preferably, the controller is adapted to selectively control the at least one first light source and the at least one second light source in accordance with a sequence of power supplied to the lamp unit. In this way, a regular lamp switch associated with the socket that the lamp unit is fitted in can be used to control the setting of the lamp unit, allowing the provision of dynamic lighting in a fully retrofit manner. Alternatively, the lamp unit may comprise a wireless receiver coupled to or forming part of the controller, wherein a dedicated remote control communicating with the controller via the wireless receiver allows for easy and full control of the lamp unit.

Further, the controller may be adapted to selectively control the at least one first light source and the at least one second light source in accordance with a voltage level or mean power supplied to the lamp unit, for instance as controlled by a dimmer associated with the socket that the lamp unit is fitted in.

Also, in one embodiment, the light sources are moveable in relation to the lamp base, so that a user beneficially may change the direction of emitted light even though the lamp base is fixed, for instance in a screw-type socket. According to another aspect of the present invention, there is provided a luminaire comprising at least one lamp unit according to the above description. This aspect exhibits similar advantages as the previously described aspect of the invention.

It is noted that the invention relates to all possible combinations of features recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the invention. Fig. 1 is a partly cross-sectional perspective view of a lamp unit according to an embodiment of the present invention.

Fig. 2 is a partly cross-sectional perspective view of a lamp unit according to another embodiment of the present invention. Fig. 3 is a partly cross-sectional side view of a lamp unit according to yet another embodiment of the present invention.

Fig. 4 is a partly cross-sectional side view of a lamp unit according to a further embodiment of the present invention.

Figs. 5a-5b are perspective views mainly from the side of luminaires comprising lamp units according to the present invention.

Fig. 6 is a flow chart of an exemplary operation of a lamp unit according to an embodiment of the present invention.

DETAILED DESCRIPTION Figs. 1-4 illustrate different lamp units 10 according to embodiments of the present invention.

The present lamp unit 10 is a replaceable component designed to produce light from electricity, preferably for illuminating a room or indoor illumination. The lamp unit 10 comprises a lamp base 12, which lamp base 12 is adapted to make an electrical connection in a socket of a light fixture or luminaire (not shown in figs. 1-4). The lamp base 12 may for instance be of the traditional screw type, for (retro)fitting of the lamp unit 10 in a traditional lamp socket of an existing luminaire, though other standard or dedicated lamp sockets could be used. For instance, a lamp base-socket combination where the lamp unit freely can rotate in relation to the socket may be preferred, since it gives freedom when it comes to selecting the direction of the emitted light.

The lamp unit 10 of figs. 1-4 further comprises at least one ('second') LED adapted to emit colored ('second') light, and at least one ('first') LED adapted to emit white ('first') light.

In the context of the present lamp unit, white light is light visually perceptible as white or whitish light, whereas colored light is light other than white having a narrower wavelength spectrum and which light is visually perceptible to humans as for instance red, green, blue, yellow, etc. LEDs providing white light may for instance be provided by partial phosphor conversion of light from blue LEDs or by combining LED dies of different colors or by combinations of phosphor converted blue LEDs and other colored LEDs to tune the color temperature of the white light, whereas the color of the light emitted by color LEDs depends on the composition and condition of the semiconducting material used, as appreciated by the skilled person. Further, a color LED of the present lamp unit may be a package containing multiple dies that emit different colors, such as RGB (Red-Green-Blue) dies, RGB and white or RGB and amber. A color light source of the present lamp unit may be a fixed color light source or a variable (multi-die) color light source. Also, a white light source of the present lamp unit may be a fixed color temperature light source or a variable color temperature light source. The top-emitting and side-emitting functionalities of the LEDs are achieved by appropriate primary optics of the LEDs, as also appreciated by the skilled person.

Fig. 1 is a partly cross-sectional perspective view mainly from the side of a lamp unit 10 according to an embodiment of the present invention. The lamp unit 10 of fig. 1 comprises one top-emitter LED 14 adapted to emit colored light, and one side-emitter LED 16 adapted to emit white light. The LEDs 14, 16 are enclosed by a glass bulb 18 or similar with or without any particular optical function. Different optical functions may be provided by making part of the bulb 18 reflecting, or by using thickness variations in the bulb 18 to refract or focus the light in a particular direction.

In the lamp unit 10 of fig. 1, the side-emitting white LED 16 is placed in front of the base 12, whereas the top-emitting colored LED 14 is placed over the at least one side- emitting white LED 16, as illustrated. That is, the top-emitter LED 14 is used to create colored light that is aimed upwards, and the side-emitter LED 16 is used to emit white light sideways, as illustrated in fig. 1 by exemplary ray-traces 22 and 24, respectively.

To improve the separation of the white and colored light, a separator 20 may be placed between the LED(s) 14 and the LED(s) 16. The separator 20 may for instance be a somewhat cup-shaped reflector, to increase the efficiency and directionality of the lamp 10. Additionally, the separator 20 may beneficially serve as a mechanical support for the top LED 14. Also, the separator 20 may be used to electrically and thermally connect the LED 14. The separator 20 is preferably made of metal.

Fig. 2 is a partly cross-sectional perspective view mainly from the side of a lamp unit 10 according to another embodiment of the present invention. In contrast to the lamp unit of fig. 1, only top emitters are used in the lamp unit 10 of fig. 2.

Namely, the lamp unit 10 of fig. 2 comprises two top-emitter LEDs 14 adapted to emit colored light, and two top-emitter LEDs 26 adapted to emit white light. The top- emitting colored LEDs 14 are placed back to back with the top-emitting white LEDs 26 on each side of a separator 20, as illustrated. During operation, the colored LEDs 14 aim light to the right, and the white LEDs 26 aim light to the left, as illustrated in fig. 2 by exemplary ray- traces 28 and 30, respectively. Like above, the separator 20 may beneficially serve as a mechanical support for the LEDs. Also, the separator 20 may be used to electrically and thermally connect the LEDs. The separator 20 is preferably made of metal.

It should be noted that in the lamp units of figs. 1 and 2, the direction of the emitted light is determined by the primary optics and the orientation of the LEDs.

Fig. 3 is a partly cross-sectional side view of a lamp unit 10 according to yet another embodiment of the present invention. In contrast to the lamp units of figs. 1 and 2, the lamp unit 10 of fig. 3 comprises secondary optics for directing or re-directing the emitted light.

Specifically, the lamp unit 10 of fig. 3 comprises three light guides 32, 34, 36 stacked on top of each other on the lamp base 12. The light guides are preferably disc-shaped, and may for instance be made of transparent or translucent plastics or glass. Associated with each light guide, there is at least one LED. Particularly, the lamp unit 10 of fig. 3 comprises one side-emitting LED 16 adapted to emit white light, one side-emitting LED 38 adapted to emit light of a first color, and one side-emitting LED 40 adapted to emit light of a second color, which second color may be the same as or different than said first color. The LEDs may for instance be arranged in centrally placed holes 42, 44, 46 in the light guides, respectively, as illustrated. Hence, also the LEDs 16, 38, 40 are stacked on top of each other.

Each light guide further comprises a circumferential out-coupling facet 48, 50, 52, wherein the orientation of the facet determines the direction of the light. The facet 48 is oriented at about -45 degrees with respect to the lamp axis 54, facet 50 is parallel to the lamp axis 54, and the facet 52 is oriented at about 45 degrees with respect to the lamp axis 54.

During operation of the lamp unit 10, light from the white LED 16 is coupled into the light guide 32 and will be reflected at the light guide-air interface of the facet 48 due to TIR towards the underside of the light guide, where it will overcome TIR due to the right or almost right angle between the light and the underside, and hence be coupled out of the light guide 32 through the underside thereof and be directed downwards, as illustrated by exemplary ray-trace 56. Likewise, light from the colored LED 40 is coupled into the light guide 36 and will be directed upwards, as illustrated by exemplary ray-trace 58. On the other hand, most light from the colored LED 38 coupled into the light guide 34 will due to the right or almost right angle between the light and the facet 50 be directly out-coupled through the facet 50, and will therefore be directed sideways, as illustrated by exemplary ray-trace 60. Usually, TIR will be enough to reflect the light at the out-coupling facets 48 and 52. However, these out-coupling facets may additionally be provided with a reflective coating to prevent leakage of light in the wrong direction.

Fig. 4 is a partly cross-sectional side view of a lamp unit 10 according to a further embodiment of the present invention. Like the lamp unit of fig. 3, the lamp unit 10 of fig. 4 comprises secondary optics for directing or re-directing the emitted light. Namely, it comprises optical elements that collimate and direct the light from different LEDs in different directions.

Specifically, the lamp unit 10 of fig. 4 comprises at least one centrally placed LED 62 adapted to emit colored light surrounded by a ring of LEDs 64 adapted to emit white light. The LEDs 62 and 64 are preferably top-emitters. Further, the lamp unit 10 comprises at least one TIR element 66 shaped and positioned so as to collimated the colored light from the LED(s) 62 in the up direction and redirect the white light from the ring of white LEDs 64 in the sideways direction, as illustrated by the exemplary ray-traces 68 and 70, respectively. The at least one TIR element 66 may for instance be funnel-shaped, and be provided as one or more air slits in an otherwise solid, lens-shaped light guide 72 placed over the LEDs, wherein the funnel is positioned over the central colored LED(s). Alternatively, one or more metallic reflectors could be used instead of the TIR element(s) with a similar result. The light guide 72 may for instance be made of transparent or translucent plastics or glass.

In another embodiment (not shown) of the present lamp unit, all LEDs of the lamp unit are multi-die LEDs (e.g. RGB or RGBW) for all directions. In this way, only white light or only colored light can be produced in all directions, but the same lamp unit can still be used (with another setting) to produce directional white and colored light by appropriately and selectively activating the dies of the different LEDs. This embodiment is indeed very flexible, but require additional control, as will be explained further below.

In yet another embodiment (not shown), the present lamp unit comprises an aluminum cube arranged such that the base of the cube is facing the lamp base. On top of the cube, at least one colored top-emitting LED is mounted, and at least one white top-emitting LED is mounted on each of the four sides of the cube. The light from the LEDs are thus aimed in five orthogonal directions. The aluminum cube provides for good thermal contact. Further, the light sources of the present lamp unit may are moveable in relation to the lamp base, so that the direction of emitted light can be altered even though the base of the lamp is fitted in a particular orientation (e.g. in case the lamp base is a screw-type lamp base fitted in a screw-type lamp socket). In one embodiment, the lamp unit comprises an internal bayonet coupling for attaching the lamp base to the rest of the lamp unit so as to allow a user to rotate the rest of the lamp unit, including the light sources, even though the lamp base is fixed. In other embodiments, electronic motorized control of the direction of the light sources may be used.

Figs. 5a-5b are schematic perspective views mainly from the side of luminaires or light fixtures comprising lamp units according to the present invention.

Fig. 5a shows a chandelier-type luminaire 74 hanging from a ceiling 76. The luminaire 74 comprises a plurality of lamp units 10 emitting colored atmospheric light 82 towards the ceiling 76, and "normal" white functional or task light 84 in other directions. The lamp units 10 in the luminaire 74 are advantageously of the type illustrated in and described in relation to fig. 1 or fig. 4.

For a luminaire (not shown) in which the lamp units are mounted up-side down, lamp units that emit colored light "downwards" are required. This may be achieved for instance with the lamp unit of fig. 3, replacing the colored LEDs with white LEDs and vice versa. Fig. 5b shows a plafonnier-type luminaire 78 hanging from a ceiling 80 over a floor 86. The luminaire 78 comprises a plurality of lamp units 10 emitting colored atmospheric light 82 towards the ceiling 80, and "normal" white functional or task light 84 towards the floor 86. Because the lamp units are placed sideways in such a luminaire, lamp units that emit white light in a sideways direction are required. Hence, lamp units of the type illustrated in and described in relation to fig. 2 are beneficially used in the luminaire 78.

In some embodiments of the present lamp unit 10, all the light sources of the lamp unit are basically switched on/off using the regular lamp switch associated with the socket that the lamp unit is fitted in. However, any of the lamp units 10 described above may additionally comprise a controller (not shown) adapted to selectively control the at least one light source adapted to emit white light and the at least one light source adapted to emit colored light. That is, the white light and the colored light may be controlled independently of each other, to create a desired illumination or lighting effect for instance in a room. Settings of the light sources and the emitted light, which settings are controlled by the controller, may include on/off state, dim or intensity level, saturation, color temperature, and hue or color.

In one embodiment, the lamp unit may comprise a wireless receiver coupled to or forming part of the controller, wherein a remote control communicating with the controller via the wireless receiver is used to selectively control the different light sources of the lamp unit. The controller and the wireless receiver are powered by the lamp unit's regular power supply, i.e. by power supplied through the lamp socket in which the lamp unit is placed. Hence, as long as the lamp unit is "generally" turned on, by the regular switch associated with the lamp socket, a user may selectively operate different colors of the lamp unit using the remote.

In another embodiment, the controller is adapted to selectively control the at least one light source adapted to emit white light and the at least one light source adapted to emit colored light in accordance with a sequence of power switches or on/off switches supplied to the lamp unit. A way to accomplish this is to use a high voltage IC that recognizes any switch on/off sequences of the lamp unit. Each time the lamp unit is turned off and on using a regular lamp switch, the lamp unit is switched to the next setting.

For instance, as illustrated in fig. 6, the first time the lamp unit is turned on (step SlO), only the at least one light source adapted to emit white light is turned on (step S12). Following a subsequent off/on switch of the lamp unit (step S14), only the at least one light source adapted to emit colored light is turned on (step S 16). Then, following yet another off/on switch of the lamp unit (step S 18), both the at least one light source adapted to emit white light and the at least one light source adapted to emit colored light are turned on (step S20). Following the next off/on switch, the cycle is repeated, and only the at least one light source adapted to emit white light is again turned on. Other exemplary operations are discussed below. Here, a switch is the fast combination of off and on again (using the regular lamp switch). In one operation, the first switch turns on the white light and the second switch starts the color of the light emitted by the at least one light source adapted to emit colored light to change following a hue circle. A switch now makes this sequence stop at the desired color. In another operation, the first switch turns on the white light and the second switch starts a saturation cycle that can be stopped at the desired saturation by a new switch. For these operations, the lamp unit preferably remembers the last settings, and when the lamp unit is turned (switched) on after being off for at predetermined time, which predetermined time is longer than the fast switch, the lamp unit returns to its last settings. It is also possible to use a conventional dimmer and map all the positions of the dimmer onto different settings such as various intensities etc. of the white light source(s) and the colored light source(s).

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. For example, various other combinations of primary optics, orientation of the light sources, light sources, and secondary optics are possible. Also, the LEDs adapted to emit white light may be replaced by LEDs adapted to emit colored light, to provide e.g. atmospheric light of a first color and task light of a second, different color.

Claims

CLAIMS:

1. A lamp unit (10), comprising: a lamp base (12); at least one first light source (16, 26, 64) adapted to emit first light having a first wavelength spectrum; and - at least one second light source (14, 38, 40, 62) adapted to emit second light having a second wavelength spectrum different from the first wavelength spectrum, wherein the lamp unit is arranged so as to emit the first light in at least one certain direction and the second light in at least one other direction.

2. A lamp unit according to claim 1, wherein the first light is white light and the second light is colored light.

3. A lamp unit according to claim 1 or 2, wherein the lamp base is adapted to be fitted in a lamp socket.

4. A lamp unit according to any preceding claim, wherein at least one of primary optics of the light sources, orientation of the light sources, and secondary optics of the lamp unit is selected such that during operation the first light is emitted in the at least one certain direction and the second light is emitted in the at least one other direction.

5. A lamp unit according to claim 4, wherein the at least one first light source comprises primary optics adapted to direct the first light in the at least one certain direction, and wherein the at least one second light source comprises primary optics adapted to direct the second light in the at least one other direction.

6. A lamp unit according to claim 4 or 5, wherein the light sources are directional light sources, and wherein the at least one first light source is oriented so as to emit the first light in the at least one certain direction and the at least one second light source is oriented so as to emit the second light in the at least one other direction.

7. A lamp unit according to any one of the claims 4-6, further comprising secondary optics adapted to direct or redirect the first light in the at least one certain direction and the second light in the at least one other direction.

8. A lamp unit according to any preceding claim, wherein the light sources are light emitting diodes (LEDs).

9. A lamp unit according to any preceding claim, wherein the at least one certain direction and the at least one other direction are generally opposite or right-angled in relation to each other.

10. A lamp unit according to any preceding claim, further comprising a controller adapted to selectively control the at least one first light source and the at least one second light source.

11. A lamp unit according to claim 10, wherein settings controlled by the controller include at least one of on/off state, dim or intensity level, saturation, color temperature, and hue or color.

12. A lamp unit according to claim 10 or 11, wherein the controller is adapted to selectively control the at least one first light source and the at least one second light source in accordance with a sequence of power supplied to the lamp unit.

13. A lamp unit according any one of the claims 10-12, wherein the controller is adapted to selectively control the at least one first light source and the at least one second light source in accordance with a voltage level supplied to the lamp unit.

14. A lamp unit according to any preceding claim, wherein the light sources are moveable in relation to the lamp base.

15. A luminaire (74, 78) comprising at least one lamp unit (10) according to any one of the claims 1-14.