| WO/2000/007214 | X-RAY TUBE |
| WO/2003/092329 | INDUCTIVELY POWERED LAMP ASSEMBLY |
| WO/2011/141732 | A SHROUD |
VERMEULEN, Paulus Albertus Maria (AE Eindhoven, NL-5656, NL)
PAPINI, Oris (AE Eindhoven, NL-5656, NL)
PREST, Alan (AE Eindhoven, NL-5656, NL)
VERBOVEN, Lieve (AE Eindhoven, NL-5656, NL)
APPELTANTS, Wilfried (AE Eindhoven, NL-5656, NL)
BENDER & WIRTH GMBH & CO. (Volmestrasse 161, Kierspe, D-58566, DE)
MARIEN, Leo Gustaaf Joanna Emiel (AE Eindhoven, NL-5656, NL)
VERMEULEN, Paulus Albertus Maria (AE Eindhoven, NL-5656, NL)
PAPINI, Oris (AE Eindhoven, NL-5656, NL)
PREST, Alan (AE Eindhoven, NL-5656, NL)
VERBOVEN, Lieve (AE Eindhoven, NL-5656, NL)
APPELTANTS, Wilfried (AE Eindhoven, NL-5656, NL)
| CLAIMS: 1. A lamp comprising at least a housing with a lamp axis, a light emitting element located in a vacuum chamber of the housing, at least two current conductors which are electrically connected with first ends to the light emitting element, and at least two contact surfaces located outside the housing which are connected to second ends of the current conductors, characterized in that the housing comprises a base located at the boundary between the vacuum chamber and the exterior, which base is transverse to the lamp axis and is provided with the contact surfaces, wherein the second end of at least a first of the two current conductors and at least a first of the two contact surfaces are located on a first projection from the base, which projection is into the exterior and substantially parallel to the lamp axis. 2. A lamp according to claim 1 comprising at least a housing, a light emitting element located in a vacuum chamber of the housing, at least two current conductors which are electrically connected with first ends to the light emitting element, and at least two contact surfaces located outside the housing which are connected to second ends of the current conductors, characterized in that the housing comprises a rotationally symmetrical base located at the boundary between the vacuum chamber and the exterior, which base is provided with the contact surfaces, wherein the second end of at least a first of the two current conductors and at least a first of the two contact surfaces are located at the central axis of the base. 3. A lamp according to claim 1 or 2, characterized in that, the second end of the second conductor and the second contact surface are located at a distance of the central axis. 4. A lamp according to claim 1, 2 or 3, characterized in that the base is provided with an electrically conducting ring concentric with the central axis, which ring comprises the second contact surface. 5. A lamp according to claim 4, characterized in that the ring extends from the exterior of the housing into the vacuum chamber, where the second end of the second conductor is connected to the ring. 6. A lamp according to one of the preceding claims, characterized in that the housing comprises a shell extending symmetrically around the central axis, a lens connected to the shell at a first end thereof and the base connected to the shell at a second end thereof. 7. A lamp according to claim 6, characterized in that the shell is provided with a reflector. 8. A lamp according to one of the preceding claims, characterized in that at least one of the contact surfaces comprises retention means for retaining the lamp in a lamp holder. 9. A lamp holder suitable to cooperate with a lamp according to one of the preceding claims, which lamp holder comprises a central axis, at least two contact elements being able to electrically contact surfaces of the lamp inserted in the lamp holder in any rotational position of the lamp about the central axis, and at least one retention element being able to retain the lamp in the lamp holder, characterized in that the retention element comprises at least one spring loaded element to apply a radial spring load on the lamp. 10. A lamp holder according to claim 9, characterized in that the spring loaded element comprises a spring loaded wire being movable in a plane extending perpendicular to the central axis of the lamp holder. 11. A lamp holder according to claim 9 or 10, characterized in that the spring loaded element comprises one of the contact elements. 12. A system comprising a lamp according to one of the preceding claims 1-7 and lamp holder according to one of the preceding claims 8-9. 13. A lamp according to claim 1, characterized in that, the second end of the second conductor and the second contact surface are located at a distance of the first current conductor and the first contact surface, preferably formed by a second projection from the base, which second projection is into the exterior. 14. A lamp according to one of the preceding claims, characterized in that the housing comprises a shell extending around the lamp axis, a lens connected to the shell at a first end thereof and the base connected to the shell at a second end thereof. 15. A lamp according to claim 14, characterized in that the shell is provided with a reflector. 16. A lamp according to one of the preceding claims, characterized in that at least one of the projections comprises retention means for retaining the lamp in a lamp holder, the retention means comprising two adjacent conical surfaces preferably having a common maximum diameter. 17. A lamp holder suitable to cooperate with a lamp according to one of the preceding claims, characterized in that the lamp holder comprises a holder axis, at least two contact elements being able to electrically contact surfaces of the lamp inserted in the lamp holder in a position of the lamp axis being substantially coinciding with the holder axis, and at least one retention element being able to retain the lamp in the lamp holder, wherein the retention element comprises at least one spring loaded element to apply a radial spring load on at least the first projection of the base of the lamp. 18. A lamp holder according to claim 17, characterized in that the spring loaded element comprises a spring loaded wire being movable in a plane extending transverse to the holder axis of the lamp holder. 19. A lamp holder according to claim 17 or 18, characterized in that the spring loaded element comprises one of the contact elements. 20 A lamp holder according to claim 17 or 18, characterized in that the holder comprises two retention elements the retention elements being able to retain the lamp in the lamp holder, preferably the retention elements each comprising at least one spring loaded element to apply a radial spring load on a respective projection of the base of the lamp. 21. A system comprising a lamp according to one of the preceding claims 1-8 and 13-16 and lamp holder according to one of the preceding claims 9-11 and 17-20, wherein in mounted state of the lamp in the lamp holder the spring loaded element rest against the first projection of the lamp base at a position between the lamp base and the maximum diameter of the conical surfaces of the projection. |
FIELD OF THE INVENTION
The invention relates to a lamp comprising at least a housing with a lamp axis, also called central axis, a light emitting element located in a vacuum chamber of the housing, at least two current conductors which are electrically connected with first ends to the light emitting element, and at least two contact surfaces located outside the housing which are connected to second ends of the current conductors.
The invention also relates to a lamp holder suitable to cooperate with such a lamp, which lamp holder comprises a central axis, also called holder axis, at least two contact elements being able to electrically contact surfaces of the lamp inserted in the lamp holder either in any rotational position of the lamp about the central axis, or in a pre-defined fixed orientation and at least one retention element being able to retain the lamp in the lamp holder.
The invention also relates to a system comprising such a lamp and such a lamp holder.
BACKGROUND OF THE INVENTION
By such a lamp which is known from W097/ 15940 of applicant, the housing is located in a reflector body and is connected to a lamp cap. The lamp cap has a substantially rotationally symmetrical shell with a central axis. Two current conductors extend through a surface of the housing at a distance of each other and at a distance of the central axis of the lamp cap. At a relatively large distance of the surface, the first and second current conductors are connected to a first central contact surface of the lamp cap and to a second contact surface of the lamp cap located at a distance of the central axis, respectively.
Such a lamp is suitable for being accommodated in a push in/push-out lamp holder. Furthermore, the rotational symmetry of the lamp cap and of the contact surfaces renders it possible to place the lamp in a lamp holder in any rotation position.
A disadvantage of the known lamp, however, is that the dimension of the lamp along the central axis is relatively long, due to which a relatively large space is required for mounting the lamp in a ceiling, for example. SUMMARY OF THE INVENTION
It is an object of the invention to provide a relatively compact lamp which is suitable for being accommodated in a push in/push-out lamp holder.
This object is achieved by the lamp according to the invention in that the housing comprises a base located at the boundary between the vacuum chamber and the exterior, which base is transverse to the lamp axis and is provided with the contact surfaces, wherein the second end of at least a first of the two current conductors and at least a first of the two contact surfaces are located on a first projection from the central axis of the base, which projection is into the exterior and substantially parallel to the lamp axis. In a first embodiment of the invention the housing comprises a rotationally symmetrical base and the second end of at least a first of the two current conductors and at least a first of the two contact surfaces are located at the central axis of the base. Thus two contact elements being able to electrically contact surfaces of the lamp inserted in the lamp holder in any rotational position of the lamp about the central axis.
Since the base is provided with the contact surfaces, the contact surfaces are located as close as possible to the vacuum chamber, due to which a compact lamp is obtained. In contrary to the lamp as known from WO97/15940, no additional lamp cap is needed. The lamp according to the invention comprises less parts due to which the manufacturing of the lamp is simpler and the costs are lower.
An embodiment of the lamp according to the invention is characterized in that the second end of the second conductor and the second contact surface are located at a distance of the central axis.
In this manner it is relatively easy to choose a distance which is large enough to be able to apply a relatively high voltage between the two contact surfaces and still have a relatively compact lamp in a direction of the central axis.
Another embodiment of the lamp according to the invention is characterized in that the base is provided with an electrically conducting ring concentric with the central axis, which ring comprises the second contact surface.
Due to the ring, the second contact surface is also ring shaped, which makes it possible to place the lamp in a lamp holder in any rotation position.
Another embodiment of the lamp according to the invention is characterized in that the ring extends from the exterior of the housing into the vacuum chamber, where the second end of the second conductor is connected to the ring. In this manner the ring can be sealed into the base, after which the second current conductor can be connected to the ring. By sealing the ring in the base a vacuum tight connection is obtained.
Yet another embodiment of the lamp according to the invention is characterized in that the housing comprises a shell extending symmetrically around the central axis, a lens connected to the shell at a first end thereof and the base connected to the shell at a second end thereof.
Since the housing itself comprises a shell and a lens a further miniaturization of the lamp is possible.
A further embodiment of the lamp according to the invention is characterized in that the shell is provided with a reflector.
By providing the shell of the housing with the reflector a compact lamp is obtained, whereby light emitted by the light emitting element is being reflected.
Yet another embodiment of the lamp according to the invention is characterized in that at least one of the contact surfaces comprises retention means for retaining the lamp in a lamp holder.
Such a retention means may comprise notches or protrusions which can cooperate with complementary means in the lamp holder to ensure a good fixation of the lamp in the lamp holder. The retention means can be connected to the complementary means in the lamp holder by pushing the lamp in the lamp holder and can be disconnected therefrom by pulling the lamp out of the lamp holder.
It is another object of the invention to provide lamp holder suitable to accommodate the lamp according to the invention.
This object is achieved by the lamp holder according to the invention in that the retention element comprises at least one spring loaded element to apply a radial spring load on the lamp.
With such a retention element a reliable retention of the lamp in the lamp holder can be obtained.
An embodiment of the lamp holder according to the invention is characterized in that the spring loaded element comprises a spring loaded wire being movable in a plane extending perpendicular to the central axis of the lamp holder.
Such a spring loaded wire is relatively compact and has small dimensions in a direction parallel to the central axis of the lamp holder and the lamp. This further promotes in an advantageous way the possibility for obtaining a compact system comprising a lamp and a lamp holder.
Another embodiment of the lamp holder according to the invention is characterized in that the spring loaded element comprises one of the contact elements.
By combining the function of retaining and contacting in the spring loaded element, a further miniaturization of the lamp holder is possible.
In an alternative embodiment of the invention the lamp comprises at least a housing with a lamp axis, a light emitting element located in a vacuum chamber of the housing, at least two current conductors which are electrically connected with first ends to the light emitting element, and at least two contact surfaces located outside the housing which are connected to second ends of the current conductors, characterized in that the housing comprises a base located at the boundary between the vacuum chamber and the exterior, which base is transverse to the lamp axis and is provided with the contact surfaces, wherein the second end of at least a first of the two current conductors and at least a first of the two contact surfaces are located on a first projection from the base, which projection is into the exterior and substantially parallel to the lamp axis.
It is advantageous in the alternative embodiment that the second end of the second conductor and the second contact surface are located at a distance of the first current conductor and the first contact surface, preferably formed by a second projection from the base, which second projection is into the exterior.
A further advantageous embodiment of the lamp according to alternative embodiment is characterized in that the housing comprises a shell extending around the lamp axis, a lens connected to the shell at a first end thereof and the base connected to the shell at a second end thereof.
In a further preferred embodiment the shell is provided with a reflector.
In the alternative embodiment of the invention the lamp is further characterized in that at least one of the projections comprises retention means for retaining the lamp in a lamp holder, the retention means comprising two adjacent conical surfaces preferably having a common maximum diameter.
The alternative embodiment of the invention also concerns a lamp holder suitable to cooperate with a lamp according the alternative embodiment of the invention as described above wherein the lamp holder comprises a holder axis, at least two contact elements being able to electrically contact surfaces of the lamp inserted in the lamp holder in position of the lamp axis being substantially coinciding with the holder axis, and at least one retention element being able to retain the lamp in the lamp holder, wherein the retention element comprises at least one spring loaded element to apply a radial spring load on at least one projection, preferably the first projection, of the base of the lamp.
A further advantageous embodiment of the lamp holder according to the alternative embodiment of the invention is characterized in that the spring loaded element comprises a spring loaded wire being movable in a plane extending transverse to the holder axis of the lamp holder.
In a further advantageous embodiment of the lamp holder according to the alternative embodiment of the invention, the lamp holder is characterized in that the spring loaded element comprises one of the contact elements.
A lamp holder according to the alternative embodiment of the invention is advantageously characterized in that the holder comprises two retention elements the retention elements being able to retain the lamp in the lamp holder, preferably the retention elements each comprising at least one spring loaded element to apply a radial spring load on a respective projection of the base of the lamp.
The alternative embodiment of the invention is also concerned with a system comprising a lamp and lamp holder according to the alternative embodiment of the invention, wherein in mounted state of the lamp in the lamp holder the spring loaded element rest against the first projection of the lamp base at a position between the lamp base and the maximum diameter of the conical surfaces of the projection.
The alternative embodiment of the invention is advantageous in that a very compact lamp as well as a very compact lamp holder can be realized suitable for a push in/push-out lamp- lamp holder system. By separating the first and second contact surfaces into separate projections of the base it is realized in a simple and very reliable way that sufficient mutual electrical isolation is achievable. This is in particular of advantage in lamps that require high voltage pulses for ignition and/or hot re-ignition, also known in the art as hot re-strike. Such pulses may be several tens of kV in magnitude.
A construction having 2 projections is furthermore advantageous for achieving a robust and precise lamp positioning with respect to the lamp holder.
The spring loaded elements can each form a contact element for the electrical connection of the lamp. Alternatively it is possible that the spring loaded element exclusively provide the mechanical retention of the lamp by applying a radial force onto the projection. The projections then will have separate contact surfaces cooperating with ditto contact elements in the lamp holder for providing the electrical connection. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail with reference to the drawings, in which
Fig. 1 is a cross section of a lamp according to the invention,
Fig. 2 is a cross section of a part of the lamp as shown in fig. 1,
Fig. 3 is a side view of a retention means of a lamp according to the invention.
Fig. 4 is a perspective view of a lamp holder according to the invention,
Fig. 5 is a perspective bottom view of an another embodiment of a lamp according to the invention retained by a retaining element of the lamp holder as shown in fig. 4,
Fig. 6 to 8 perspective views of embodiments of lamp and lamp holder of an alternative embodiment of the invention.
Like parts are indicated by the same reference numbers in the figures.
DETAILED DESCRIPTION OF EMBODIMENTS
Fig. 1-3 show an embodiment of a lamp 1 according to the invention. The lamp 1 is provided with a housing 2 comprising a shell 3 made of glass and extending symmetrically around a central axis 4, also called lamp axis. The shell 3 comprises a cylindrical part 5 and a conical part 6 connected to the cylindrical part 5. At a side remote of the cylindrical part 5, a lens 7 is connected to the conical part 6 in an air tight manner. Inside the conical part 6 a reflector 8 is located. The housing 1 is further provided with a cylindrical base 9 which is sealed in an air tight manner to the cylindrical part 5 of the shell 3. The base 9 can be made of glass. In the housing 2 a vacuum chamber 10 is located. The lamp 1 is further provided with a light emitting element 11 comprising a charge vessel 12 and two contacting elements 13, 14 extending on both sides of the charge vessel 11 in a direction along the central axis 4. Each contacting elements 13, 14 is connected to a first end 15, 16 of a current conductor 17, 18 respectively. The first current conductor 17 extends along the central axis 4 and through the base 9 to the exterior of the housing 2. The second end of the first current conductor 17 forms a first contact surface 19 to be contacted by a lamp holder (not shown). The second current conductor 18 extends from the contacting element 14 at a distance of the central axis 4 towards the base 9. The base 9 is provided with an electrically conducting ring 20 which located at the outside of the housing 2 concentric with the central axis 4. The ring 20 is provided with a protrusion 21 extending through the base 9 into the vacuum chamber 10. A second end 22 of the second current conductor 18 is connected to the protrusion 21.
The concentric ring 20 forms a second contact surface to be contacted by a lamp holder (not shown). The distance between the first and second contact surface (being the distance between the first current conductor 17 and the ring 20) is large enough so that it is possible to safely apply a voltage of a few kV, like 4-5 kV between the contact surfaces, which voltage is needed for the ignition of the charge vessel 12.
The lamp 1 can be manufactured by providing the shell 3 with the reflector 8 and the lens 7. Then, the base 9 is provided with the ring 20, the light emitting element 11 and the current conductors 17, 18 as is shown in fig. 2. Subsequently, the shell 3 and the base 9 are connected to each other by means of a seal 23, whilst vacuum is created in the vacuum chamber 10.
Fig. 3 shows an embodiment of a retention means 25 provided on the first central current conductor 17. The retention means 25 comprises two conical surfaces 26, 27. The retention means 25 may cooperate with complementary means in the lamp holder like a spring. When pushing the lamp 1 into the lamp holder, the spring will be moved away by means of the conical surface 26. As soon as the conical surface 27 is located opposite the spring, the spring will be moved back and apply a holding force on the conical surface 27. The lamp 1 can be removed by pulling at the lamp 1 , whereby the spring will be moved away by means of the conical surface 27.
Fig. 4 shows a perspective view of a lamp holder 31 according to the invention comprising a cylindrical holder 32 with a flat top surface 33 forming a contact element 34 and a centrally located passage 35. At the bottom of the passage 35 another contact element 36 is located. In the wall of the passage 36 a retention element 37 (see fig. 5) is located. The retention element 37 is made of a wire and comprises a first wire part 38 for mounting the retention element 37 in the holder 32, a second wire part 39 connected to the first wire part 38 and extending perpendicular to the first wire part 38, a third wire part 40 connected to the second wire part 39 and extending perpendicular to the first and second wire parts 38,39 and a fourth wire part 41 connected to the third wire part 40 and extending parallel to the second wire part 39. The distance between the second and fourth wire parts 39, 41 is smaller than the diameter of the passage 39. The second and fourth wire parts 39, 41 can be moved apart in a plane perpendicular to the central axis of the passage 39 under spring force of the wire parts.
Fig. 5 shows a perspective bottom view of an embodiment of a lamp according to the invention, provided with a pen 42 extending along the central axis of the lamp and a conducting ring 20. The pen 42 is provided with retaining means comprising two conical surfaces 26, 27. The end of the pen 42 is provided with the first contact surface 19. The maximum diameter of the two conical surfaces 26, 27 is smaller than the diameter of the passage 39 but larger than the distance between the second and fourth wire parts 39, 41.
To connect the lamp to the lamp holder 31 , the pen 42 is inserted into the passage 39. By pulling at the lamp in a direction parallel to the central axis 4, the conical surface 26 will push the wire parts 39,41 apart. As soon as the maximum diameter of the two conical surfaces 26, 27 has passed the wire parts 39, 41 the wire parts 39, 41 will exert a force on the conical surface 27 pulling the conical surface 27 towards the contact element 36 until the contact surface 19 contacts the contact element 36. At the same time contact is being made between the conducting ring 20 and the contact element 34 at the flat top surface 33.
Preferably, the diameter of the wire parts is relatively small to reduce friction.
It is also possible to provide the shell 3 with a first electrically conducting metal ring and to provide the base with a second electrically conducting metal ring, whereby the rings are being welded to each other.
It is also possible to provide the ring 20 with retaining means like double conical surfaces, for example.
Preferably, the lamp holder and the lamp are designed to have a seating plane at the lamp holder and at the lamp, which seating planes touch each other before the conical surface 27 fully passed the wire parts 39, 41. This allows the system to apply a force to permanently pull the lamp against the lamp holder thus performing a good fit.
The inwards applied force of the wire parts 39, 41 has to perform an axial pull force that is considerably stronger than the contact force applied to the contact element at the central pin's end.
The angle of each of the slopes of conical surfaces 26, 27 may be chosen independently to vary the needed insertion force and the withdrawal force.
Preferably, when the lamp is mounted in the lamp holder, the lamp is prevented against tilting to such an amount that the retaining member could leave the retaining element.
The radially spring loaded element in the lamp holder may be only one part with spring load in only one direction and thus pressing the lamp against a rigid part of the lamp holder, which rigid part should preferably made from insulating material or conductive material. It is also possible to provide the ring 20 with a cylindrical part extending away from the housing 2 over a distance similar to the length of the first current conductor.
It is also possible to use several second contact surfaces located at a distance of each other and of the central axis instead of a ring shaped contact surface.
The dimension of the lamp 1 in the direction of the central axis 4 can be about
50 mm.
It is also possible to provide both the first contact surface and the second contact surface on a centrally located pen, whereby an insulation part is provided on the pen between the contact surfaces.
In the alternative embodiment of the invention as depicted in fig. 6 to 8 the lamp 30 has a lamp axis indicated by 100 and the holder 310 has a holder axis indicated by 300. In a system of lamp holder with mounted lamp as depicted in the way of an exploded view in Fig. 8 the lamp axis and the holder axis are substantially coinciding with each other.
The projections of the base of the lamp are numbered 420, 421. Each projection comprises two adjacent conical surfaces 260, 270 in the shown case having a common maximum diameter. The conical surfaces function as retention means for retaining the lamp in a lamp holder.
The lamp holder 310 has two passages 350, 351 each provided with a spring loaded element 390, 391. The spring loaded elements are constructively equivalent to the retention element 37 as shown in Fig. 3.
The passages 350, 351 can be constructively equal to the passage 35 as shown in Fig.3. In the shown embodiment the passages 350, 351 are not provided with contact element at the bottom of the passages for further electrical connection. The spring loaded elements 390, 391 both providers for the radial spring load on the lamp base projections as well as for the contact elements contacting the contact surfaces of the lamp base for the electrical connection of the lamp. In an alternative construction the spring loaded elements 390, 391 only provide for the mechanical aspect of retention force on the lamp base projection, whilst a bottom contact provides for the electrical connection with contact surfaces of the projections.
The holder 310 has a rim 330, which at its inside is provided with one or more slots 331. By means of these slots a pre-defined lamp orientation has been fixed.