Patent Application
20100207500
The invention relates to a lamp, a luminaire and a system including a lamp and a luminaire.
In order to dissipate heat generated in a lamp, various methods are described such as thermoelectric cooling or air cooling with a fan, for example as in US 2003/040200 A. However, the previously known methods are either not very efficient or are comparatively complex or bulky.
The object of the invention is therefore to provide an option which has improved thermal properties of light-emitting means, in particular lamps and luminaires, and at the same time can be implemented comparatively easily and is space-saving.
This object is achieved by means of a lamp as claimed in claim 1, a luminaire as claimed in claim 26 and a system as claimed in claim 29.
The lamp has a housing and at least one heat source connected directly or indirectly thereto. The lamp also has a base for connection to or for engagement with a lampholder, wherein the base has at least one heat dissipation surface, and at least one heat source is thermally conductively connected to at least one heat dissipation surface.
Thermally conductive is in particular understood to mean a connection which has a thermal conductivity coefficient of at least 5 W/(m·K), especially of greater than approximately 15 W/(m·K), as is typical for Cr—Ni steel. Also included are the thermal conductivities of thermally conductive pastes, films and adhesives. The thermal conductivity makes it possible to dissipate a significant quantity of heat from the heat source.
This provides the possibility of a lamp in which the heat generated in the lamp can be transmitted efficiently via a “base/lampholder connection” to the luminaire or illumination device, to which the lamp is connected during operation. This device manages without any voluminous or complex active elements.
The heat source is generally a heat-emitting element and can in particular include a light source and/or a driver circuit.
The light source can in particular comprise at least one light-emitting diode and/or a discharge lamp. In the case of a discharge lamp, a compact fluorescent lamp, in particular an electrodeless compact fluorescent lamp (RCFL) or a high intensity discharge lamp (HID) is preferred. Light-emitting diode can in this case be understood to mean individual light-emitting diodes, for example monochromatic or white LEDs, but also groups or clusters of LEDs which together emit an additive color mixture. Examples of LED clusters are clusters including the primary colors R, G and B, in particular of the type RGGB. Also included are chains including interconnected LEDs.
Preferably, the base is a bayonet-type base, wherein said base protrudes at one end (toward the (lower) side facing the lampholder) and electrical contacts are formed laterally on said base. The electrical contacts are typically electrically insulated from the rest of the base. The base outside of the electrical contacts can serve completely as a heat dissipation surface. However, it may also be preferable for only an underside (which is opposite the lampholder) or only side faces of the base to serve as a heat dissipation surface. In addition, the heat dissipation surface can include one or more locally limited zones.
For reliable electrical contact-making, it is preferable if the electrical contacts are bow contacts which are located on webs extending laterally from the base; in particular if the contacts are arranged at the end.
The electrical contacts are preferably arranged radially symmetrically about the base. Two or four electrical contacts are preferred, but the arrangement is not restricted thereto.
Alternatively, however, the base can also be in the form of a screw-type base, for example with a heat dissipation surface which points downwards in the center.
Alternatively, a lamp may be preferred in which the base includes at least one locking piece or opposing locking piece for a ball lock.
Also preferred is a base which has at least one laterally arranged electrical contact.
Alternatively or in addition, the base can have at least one electrical contact which is arranged at the end, in particular centrally.
Then, particularly preferred is a lamp in which the at least one electrical contact arranged on the underside at the same time represents a heat dissipation surface.
Alternatively, the base may be a base in accordance with the so-called Gardena principle or design.
Generally preferred is a lamp in which a heat-conducting element is provided for the thermally conductive connection between the at least one heat source and the at least one heat dissipation surface.
The heat-conducting element includes a material with high thermal conductivity, in particular a material having a thermal conductivity coefficient of at least approximately 5 W/(m·K), in particular more than approximately 15 W/(m·K), as is typical for Cr—Ni steel, and more preferably of more than approximately 50 W/(m·K) and especially preferably of more than 300 W/(m·K), for example including copper.
Then, a heat-conducting element which includes a metal line is preferred.
However, a heat-conducting element which has a heat pipe can also be preferred for particularly effective heat dissipation.
Alternatively or in addition, the heat-conducting element includes the lampholder which can have metallic inner faces, for example.
In general, it may be preferable if at least one heat dissipation surface is at the same time an electrical contact.
For effective heat dissipation, however, a lamp may also be preferable in which at least one heat source is applied to a circuit board, and the circuit board is fitted directly on the base or on a heat-dissipating housing. As a result, the heat transport path is shortened and the heat dissipation is intensified. The circuit board then preferably has a metal core or a metal surface on the rear side for uniform heat distribution.
For direct and particularly effective heat dissipation, however, a lamp can also be preferred in which at least one heat source, for example an LED, a fluorescent tube or driver electronics, is fitted directly on the heat-conducting housing or on the base, for example by means of a thermally conductive adhesive.
In addition, a lamp is preferred in which the height of the base is no more than 15 mm, preferably less than 9 mm, further preferably less than 5 mm.
For effective heat transfer between the lamp and lampholder, at least one heat dissipation surface is preferably covered at least partially by a thermally conductive film.
Also preferred is a lamp as claimed in one of the preceding claims, which additionally has a cylindrical extension on the base, in which extension an electronic and/or electrical circuit, or a part thereof, is accommodated.
The object is also achieved by a lampholder for accommodating a lamp as described above or by a luminaire with such a lampholder.
Preferred is a luminaire with heat dissipation surfaces, which are in thermal contact with the heat dissipation surfaces of the lamp when the lamp is inserted.
Preferably, the heat dissipation surfaces are thermally conductively connected to a cooling element, for example a cooling plate or cooling ribs of the luminaire.
The object is also achieved by means of a system with a lamp as described above and a luminaire as described above.
Preferably, a thermal bonding means is provided between the lamp and the lampholder, for example by means of a thermally conductive paste or in the form of a thermally conductive film. The film is preferably easily deformable with a high degree of elasticity in order to enlarge the contact surface or is plastically deformable. The thermal bonding means can be formed as part of the base or as a separate component part.
For a firm fit, a system is preferred in which the base of the lamp and the lampholder have a deviation in form, at least in sections.
The invention will be shown in more detail schematically using the following exemplary embodiments. In this case, identical or functionally identical elements can be provided with the same reference numerals. It should be clear that the invention is not restricted to the embodiments shown.
In order to dissipate the waste heat generated by the light-emitting diodes 3 during operation, each of the light-emitting diodes 3 is connected to a heat-conducting element 7, via which the waste heat is dissipated through the base 5 into the lampholder. For this purpose, the base 5 has a plurality of heat dissipation surfaces 7a, which correspond to the outer surfaces or undersides of the heat-conducting elements 7, possibly with an additional layer, for example consisting of thermally conductive paste or film. The heat dissipation surfaces 7a are in good thermal contact with a corresponding thermally conductive zone or a plurality of zones of the lampholder. The heat is conducted further to a cooling zone 8 in or by the lampholder 6.
In the exemplary embodiment shown, the heat-conducting element 7 in each case includes a heat pipe; the lampholder can have corresponding heat pipes (not depicted), which conduct the heat towards the cooling zone 8.
In addition, electrical or electronic control components, which emit heat, can also be connected to the lampholder via heat-conducting elements 7.
Alternatively, the heat-conducting elements are not in the form of heat pipes, but comprise a material with good thermal conductivity, such as copper, silver or gold.
Alternatively, a common heat dissipation surface for a few or all of the heat-conducting elements 7 can be provided.
In this case, the base includes a cylindrical extension (“rucksack”), in which an electronic and/or electrical circuit, or a part thereof, is accommodated. Preferably, ballast electronics, in particular a smoothing capacitor, are accommodated at least partially in the rucksack; this being the case even when using a fluorescent lamp instead of the LED 3. The lampholder, which is not illustrated here for reasons of improved clarity, in this case has a corresponding recess. The rucksack 12 is designed to be thermally conductive so as to store heat. The rucksack 12 also has electrical or electromechanical contact-making and a thermally conductive connection to the luminaire or the lampholder 10 thereof.
For thermal dissipation, a heat conductor 24 of the lamp extends into a cutout in a relatively wide heat conductor 25 of the lampholder 18. The associated contact surface corresponds to the heat dissipation surface 24a. For improved heat transfer between the base 17 and the lampholder 18, a film 26 consisting of thermally conductive metal is provided between the heat conductors 24, 25. The heat conductors 24, 25 are each in the form of heat pipes. The heat conductors 24, 25 can be in the form of electrical conductors.
In one variant, the lampholder is designed in such a way that a voltage at a first voltage level, for example 230 V, is provided via the lateral contacts 22, and a voltage at a second voltage level, for example 24V, is provided at the lower or end-side contact, which in this case is formed by the heat conductor 25. As a result, the lampholder 18 can be suitable, without being changed, for lamps with a voltage supply at the first voltage level with lateral contacts 23 and, alternatively, for lamps with a voltage supply at the second voltage level with lower contacts 24.
The base 31 is in the form of a bayonet-type base which has a height h1 in that region which engages or interacts with the lampholder 28 and is equipped with base webs 32, which are lateral with respect to a longitudinal axis A.
By means of rotating the lamp 27 in or into the lampholder 28, the lamp 27 is pressed firmly against the lampholder 28. In order to increase the pressure, the base 31 and the lampholder 28 can have at least sections which deviate from their basic shape, which is in this case cylindrical, at the contact region, for example be designed to be slightly conical or elliptical. The height h1 in this case is less than 5 mm.
The invention is of course not restricted to the embodiments shown or the described elements thereof.
Thus, compact fluorescent lamps and/or light-emitting diodes, for example, can be used as light sources; but other suitable light sources can also be used.
The driver circuit is not restricted to a particular embodiment and can contain any desired suitable electrical and/or electronic elements. Particularly preferred is, for example, an arrangement of LEDs connected back-to-back in parallel. Also, the driver circuit can include a simple rectifier, for example, in which the light-emitting diode, the light-emitting diode cluster or LED chain are preferably arranged in a branch of the rectifier. Also, the driver preferably includes a current limiter, for example, a resistor or a current regulator. The driver can also include a switched mode power supply, preferably a so-called flyback converter.
The circuit board can have a substrate including PCB, FR4 or MC-PCB, for example.
The base preferably has a very short physical height for insertion into a corresponding lampholder. Said lampholder can preferably have a height of up to 15 mm, particularly when measured without the rucksack. For the case in which a rucksack is used, an increased height can also be advantageous since the rucksack, as part of the base, is sunk into the cutout provided in the lampholder.
The number and/or arrangement of the contacts both of the lamp and of the lampholder can be assigned to coding information, for example with respect to the lamp type or a voltage class.
In particular, the heat pipes, but also other metallic heat dissipation elements can generally also be in the form of electrical contacts. The heat dissipation elements can also include nonmetallic conductive elements, for example, electrically conductive ceramics.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 042 978.0 | Sep 2007 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2008/007392 | 9/10/2008 | WO | 00 | 3/10/2010 |
