Semiconductor lamp

Abstract

Semiconductor lamp having a straight, translucent tube whose open end faces can be closed by means of respective end caps, which end caps are plug-connected to the tube, a circuit board which is equipped with at least one semiconductor light source is installed in the tube and is in contact with at least one of the end caps, wherein both end caps are mechanically connected to one another by means of a connection element running in the tube, at least one of the end caps is arranged such that it can be displaced longitudinally with play with respect to the tube and thermal expansion of the connection element in a longitudinal direction of the tube is smaller than thermal expansion of the tube and wherein the connection element is snap-fitted to at least one of the end caps. The invention can for example be used for retrofit or replacement lamps for conventional elongate lamps (e.g., fluorescent lamps and tube lamps).

Claims

1. A semiconductor lamp comprising: a straight, translucent tube whose open end faces are configured to be closed by means of respective end caps, which end caps are configured to be plug-connected to the tube; and a circuit board which is equipped with at least one semiconductor light source which is configured to be accommodated in the tube and is configured to be contacted by at least one of the end caps; wherein: both end caps are configured to be mechanically connected to one another by means of a connecting element extending in the tube, wherein the connecting element is a strip-shaped, metallic connecting element, wherein the connecting element comprises at least one fold-over region for snap-fitting to a respective end cap, said fold-over region comprising a snap-in cut-out; at least one of the end caps is arranged such that it is configured to be displaced longitudinally with play with respect to the tube; thermal expansion of the connecting element in a longitudinal direction of the tube is smaller than thermal expansion of the tube; and the connecting element is configured to be snap-fitted to at least one of the end caps.

2. The semiconductor according to claim 1, in which the snap-in cut-out is configured to be brought into engagement with a snap-in protrusion of a respective end cap.

3. The semiconductor lamp according to claim 1, in which the circuit board rests loosely on the connecting element.

4. The semiconductor lamp according to claim 1, in which the connecting element is integrated into the circuit board.

5. The semiconductor lamp according to claim 1, in which the tube is a plastic tube.

6. The semiconductor lamp according to claim 1, in which the tube is formed on the inside as a linear guide at least one of for the circuit board and for the connecting element.

7. The semiconductor lamp according to claim 6, in which the tube comprises inwardly projecting protrusions which are configured to hold the circuit board perpendicular to the longitudinal direction in the tube.

8. The semiconductor lamp according to claim 7, in which the connecting element is arranged in a cavity formed between the circuit board and the tube.

9. The semiconductor lamp according to claim 1, in which the tube is equipped on the inside with a receiver for the connecting element which is configured to hold the connecting element in a form-fitting manner in a transverse direction.

10. The semiconductor lamp according to claim 1, in which the circuit board is configured to be electrically connected by means of an electrical plug-in contact to at least one end cap, wherein the plug-in contact is displaceable towards its plug-in contact counterpart while retaining its electrical contact.

11. The semiconductor lamp according to claim 1, in which the semiconductor lamp is a retrofit lamp.

12. A semiconductor lamp comprising: a straight, translucent tube whose open end faces are configured to be closed by means of respective end caps, which end caps are configured to be plug-connected to the tube; and a circuit board which is equipped with at least one semiconductor light source which is configured to be accommodated in the tube and is configured to be contacted by at least one of the end caps; wherein: both end caps are configured to be mechanically connected to one another by means of a connecting element extending in the tube, wherein the connecting element is a strip-shaped, metallic connecting element, wherein the connecting element comprises at least one snap-in cut-out for snap-fitting to a respective end cap, adjoining which snap-in cut-out is a securing region protruding inwards in the manner of a ramp towards a nearest open end face; at least one of the end caps is arranged such that it is configured to be displaced longitudinally with play with respect to the tube; thermal expansion of the connecting element in a longitudinal direction of the tube is smaller than thermal expansion of the tube; and the connecting element is configured to be snap-fitted to at least one of the end caps.

13. The semiconductor according to claim 12, in which the at least one snap-in cut-out is configured to be brought into engagement with a snap-in protrusion of a respective end cap.

14. The semiconductor lamp according to claim 12, in which the circuit board rests loosely on the connecting element.

15. The semiconductor lamp according to claim 12, in which the connecting element is integrated into the circuit board.

16. The semiconductor lamp according to claim 12, in which the tube is a plastic tube.

17. The semiconductor lamp according to claim 12, in which the tube is formed on the inside as a linear guide at least one of for the circuit board and for the connecting element.

18. The semiconductor lamp according to claim 17, in which the tube comprises inwardly projecting protrusions which are configured to hold the circuit board perpendicular to the longitudinal direction in the tube.

19. The semiconductor lamp according to claim 18, in which the connecting element is arranged in a cavity formed between the circuit board and the tube.

20. The semiconductor lamp according to claim 12, in which the tube is equipped on the inside with a receiver for the connecting element which is configured to hold the connecting element in a form-fitting manner in a transverse direction.

21. The semiconductor lamp according to claim 12, in which the circuit board is configured to be electrically connected by means of an electrical plug-in contact to at least one end cap, wherein the plug-in contact is displaceable towards its plug-in contact counterpart while retaining its electrical contact.

22. The semiconductor lamp according to claim 12, in which the semiconductor lamp is a retrofit lamp.

23. A semiconductor lamp comprising: a straight, translucent tube whose open end faces are configured to be closed by means of respective end caps, which end caps are configured to be plug-connected to the tube; and a circuit board which is equipped with at least one semiconductor light source which is configured to be accommodated in the tube and is configured to be contacted by at least one of the end caps; wherein: both end caps are configured to be mechanically connected to one another by means of a connecting element extending in the tube, wherein the connecting element is a strip-shaped, metallic connecting element, wherein the connecting element comprises at least one snap-in cut-out for snap-fitting to a respective end cap, out of which snap-in cut-out a material region is folded over towards a nearest open end face; at least one of the end caps is arranged such that it is configured to be displaced longitudinally with play with respect to the tube; thermal expansion of the connecting element in a longitudinal direction of the tube is smaller than thermal expansion of the tube; and the connecting element is configured to be snap-fitted to at least one of the end caps.

24. The semiconductor according to claim 23, in which the at least one snap-in cut-out is configured to be brought into engagement with a snap-in protrusion of a respective end cap.

25. The semiconductor lamp according to claim 23, in which the circuit board rests loosely on the connecting element.

26. The semiconductor lamp according to claim 23, in which the connecting element is integrated into the circuit board.

27. The semiconductor lamp according to claim 23, in which the tube is a plastic tube.

28. The semiconductor lamp according to claim 23, in which the tube is formed on the inside as a linear guide at least one of for the circuit board and for the connecting element.

29. The semiconductor lamp according to claim 28, in which the tube comprises inwardly projecting protrusions which are configured to hold the circuit board perpendicular to the longitudinal direction in the tube.

30. The semiconductor lamp according to claim 29, in which the connecting element is arranged in a cavity formed between the circuit board and the tube.

31. The semiconductor lamp according to claim 23, in which the tube is equipped on the inside with a receiver for the connecting element which is configured to hold the connecting element in a form-fitting manner in a transverse direction.

32. The semiconductor lamp according to claim 23, in which the circuit board is configured to be electrically connected by means of an electrical plug-in contact to at least one end cap, wherein the plug-in contact is displaceable towards its plug-in contact counterpart while retaining its electrical contact.

33. The semiconductor lamp according to claim 23, in which the semiconductor lamp is a retrofit lamp.

Description

(1) The properties, features and advantages of this invention described above and the way in which they are achieved, will be more clearly and distinctly understood in conjunction with the following schematic description of embodiments which will be explained in greater detail in connection with the drawings. For the sake of clarity, identical or equivalent elements can be provided with the same reference numbers.

(2) FIG. 1 shows a sectional diagram in lateral view of a detail from a semiconductor lamp according to a first embodiment;

(3) FIG. 2 shows a sectional diagram in oblique view of a further detail of the semiconductor lamp according to the first embodiment;

(4) FIG. 3 shows in oblique view a detail from a connecting element of the semiconductor lamp according to the first embodiment;

(5) FIG. 4 shows the semiconductor lamp according to the first embodiment in cross-sectional view;

(6) FIG. 5 shows in oblique view a detail from a connecting element of a semiconductor lamp according to a second embodiment;

(7) FIG. 6 shows a sectional diagram in oblique view of a detail of the semiconductor lamp according to the second embodiment;

(8) FIG. 7 shows in oblique view a detail from a connecting element of a semiconductor lamp according to a third embodiment;

(9) FIG. 8 shows a sectional diagram in oblique view of a detail of the semiconductor lamp according to the third embodiment;

(10) FIG. 9 shows a sectional diagram in oblique view of a semiconductor lamp according to a fourth embodiment; and

(11) FIG. 10 shows the semiconductor lamp according to the fourth embodiment in cross-sectional view.

(12) FIG. 1 shows a sectional diagram in lateral view of an end-side portion of a semiconductor lamp 1 according to a first embodiment. FIG. 2 shows the semiconductor lamp 1 in part as a sectional diagram in oblique view.

(13) The semiconductor lamp 1 intended as a retrofit lamp, e.g. to replace a T8 fluorescent lamp, comprises a straight, translucent tube 2 having a hollow cylindrical basic shape made of transparent or opaque plastic. The tube 2 comprises, for example, open end faces 3 on both sides which can be closed by means of respective end caps 4.

(14) For this purpose, the end caps 4 have a hollow cylindrical shape which is open in the direction of the tube 2 so that they can be inserted into the tube 2 up to a predetermined maximum penetration depth, e.g. in the manner of a plug. Here, the maximum penetration depth is predetermined by a casing-side, annular external prominence 5 which serves as a limit stop for the tube 2. The end caps 4, however, should not be inserted into the tube 2 to the maximum in order to leave a longitudinal play d in a longitudinal direction L of the tube 2. The end caps 4 fit tightly into the tube 2 radially or with only a small amount of radial play.

(15) A driver 6, having a driver circuit board 7, which is equipped with a plurality of driver modules 8, is accommodated in the interior of the end cap 4 shown. Two electrically conductive contact pins 11, which are electrically connected to the driver 6 (e.g. via a contact strip 12) and can be fed via the electrical supply signals, lead through an end face 10 of the end cap 4 directed away from the tube 2. The driver 6 converts the electrical supply signals into electrical operating signals for semiconductor light sources in the form of LEDs 17, for example.

(16) The driver circuit board 7 is inserted into an electrical plug-in contact 15 in a longitudinally displaceable manner and electrically contacts the latter. The electrical plug-in contact 15 is arranged on an upper side of a strip-shaped circuit board 16 which is also equipped with a plurality of LEDs 17 arranged along the longitudinal direction L. The plug-in contact 15 is displaceable towards the driver circuit board 7 while maintaining an electrical contact, which is particularly advantageous for preventing stresses in the circuit board 16.

(17) The circuit board 16 rests loosely with its underside on a strip-shaped connecting element in the form of a steel strip 18. The steel strip 18 is snap-fitted at one end with the end cap 4, here with an end cap contact part 19 comprising the contact pins 11. The end cap 4 can thus also be regarded as a system composed of the end cap contact part 19 and the driver 6.

(18) The snap-fit-mechanism comprises a snap-in protrusion 20 of the end cap 4 projecting outwards on the casing side, said protrusion comprises a chamfer in an insertion direction E of the end cap 4 into the tube 2. On the side of the snap-in protrusion 20 directed away from the tube 2, the end cap 4 also has a recess 21 introduced into the outer circumferential surface of the end cap 4.

(19) As snap in counterpart, the steel strip 18 comprises a snap-in cut-out 22 for engaging with the snap-in protrusion 20. The steel strip further comprises a protrusion directed inwards in the form of a fold-over 23 for accommodation in the recess 21.

(20) The end cap 4 shown is rigidly connected mechanically via the steel strip 4 to an end cap (not illustrated) sealing the other end face of the tube 2. The connection of the two end caps 4 can be free from play in the longitudinal direction L or may have only slight play. The two end caps 4 can be of identical shape. Due to the mechanically rigid connection of the two end caps 4 to each other via the steel strip 18 and due to the existing play d, the tube 2 is arranged so as to be (longitudinally) displaceable in the longitudinal direction L (in and against the direction of insertion E) towards the end caps 4.

(21) A temperature-dependent change in length of the semiconductor lamp 1 as such is substantially determined by the comparatively small change in length of the steel strip 18. As the longitudinal expansion coefficient of the steel of the steel strip 18 is considerably lower than that of the plastic of the tube 2, the play d becomes smaller when heated and larger when cooled. Therefore, a linear expansion of the tube 2 is compensated by a change in the play d. The size of the play d can be specified simply by knowing the longitudinal expansion coefficient of the steel strip 18 and of the plastic tube 2 as well as the desired temperature range (e.g. from 20 C. to 70 C., from 0 C. to 50 C. or similar). FIG. 3 shows an end-side detail from the connecting element 18. On the end side, the connecting element 18 comprises the fold-over region 23 which has been achieved, for example, by bending a flat steel strip by 180. The fold-over region 23 comprises two layers 23a and 23b lying on top of each other, into which the respective congruent cut-outs have been introduced in order to form the snap-in cut-out 22 together.

(22) FIG. 4 shows the semiconductor lamp 1 in a cross-sectional view through the tube 2 at the level of an LED 17. The tube 2 is formed on the inside as a linear guide for the circuit board 16 and for the steel strip 18. For this purpose, the tube 2 comprises inwardly projecting protrusions 24 which hold the circuit board 16 perpendicular to the longitudinal direction L in the tube 2. The protrusions 24 can extend over a largish length or even over the entire length of the tube 2 or, for example, there may be a plurality of protrusions 24 spaced apart in the longitudinal direction L.

(23) Together the circuit board 16 and the tube 2 form a cavity 25 in which the steel strip 18 is arranged. In this case, the steel strip 18 lies in a groove-like receiver 26 and is held therein by the circuit board 16. This has the advantage that the steel strip 18 is prevented from bending by the circuit board 16 and as a result from changing its desired length, for example.

(24) FIG. 5 shows in an oblique view a detail from a steel strip 32 serving as a connecting element of a semiconductor lamp 31, said semiconductor lamp also comprising the end cap 4, the circuit board 16 and the tube 2. The steel strip 32 also comprises a snap-in cut-out 33 in its end region for engaging with the snap-in protrusion 20 of the end cap 4, as shown in FIG. 6.

(25) A securing area 34 protruding in the manner of a ramp adjoins the snap-in cut-out 32 in the direction of the open end face (here: against the direction of insertion E of the end cap 4). The securing region 34 is arranged in the recess 21 of the end cap 4. When the end cap 4 is inserted, the snap-in protrusion 20 can slide in over and past the securing region 34 but is then prevented by said securing region from sliding out.

(26) FIG. 7 shows in an oblique view a detail from a steel strip 42 serving as a connecting element of a semiconductor lamp 41. The steel strip 42 also comprises a snap-in cut-out 43 in its end region for engaging with the snap-in protrusion 20 of the end cap 4 of the semiconductor lamp 41, as shown in FIG. 8. However, a material area 44 from the snap-in cut-out 43 is now folded over in the direction of a nearest open end face of the tube 2 (here: against the direction of insertion E of the end cap 4). The material region 44 is arranged in the recess 21 of the end cap 4.

(27) FIG. 9 shows a sectional diagram in oblique view of a detail from a semiconductor lamp 51. Unlike the semiconductor lamps 1, 31 and 41, the semiconductor lamp 51 comprises a metallic connecting element which is integrated in a circuit board 52 and can serve, for example, as a core thereof. A simple snap-in cut-out 53 is then provided for engaging with the snap-in protrusion 20.

(28) FIG. 10 shows the semiconductor lamp 51 in cross-sectional view through an LED 17. A tube 54 of the semiconductor lamp 51 is flattened on the back side of the circuit board 52 to prevent a gap between a back side of said circuit board 52 and said tube 54 in order to facilitate improved heat transfer from the circuit board 52 to the tube 54.

(29) The semiconductor lamps 1, 31, 41 and 51 shown in the embodiments can be assembled particularly easily by inserting the circuit board and the metal strip (possibly integrated therein) into the tube and then inserting at least one end cap into said tube. As a result of the insertion process, the end cap is advantageously also snapped into the metal strip and inserted into the electrical plug-in contact of the circuit board. The other end cap can be mounted analogously or can have already been connected to the tube before insertion of the circuit board and the metal strip therein.

(30) Although the invention has been illustrated and described in greater detail using the embodiments shown, the invention is not limited thereto and a person skilled in the art may derive other variations therefrom without departing from the scope of protection of the invention.

(31) Thus, instead of the metal strip, for example, a connecting elementin particular strip-shapedmade of glass, circuit board material (such as FR4, CEM1, etc.) or ceramic can also be used. In particular, the connecting element itself can be a circuit board base body, in particular without metallisation.

(32) Generally, one, a etc. may be understood to mean a single figure or a plurality, particularly in the sense of at least one or one or more, etc., as long as this is not explicitly excluded, e.g. by the expression exactly one.

(33) A specified figure may also include exactly the number and also a customary tolerance range, as long as this is not explicitly excluded.

REFERENCE NUMBERS

(34) 1 Semiconductor lamp 2 Tube 3 End face 4 End cap 5 External prominence 6 Driver 7 Driver board 8 Driver component 10 End face 11 Contact pin 12 Contact strip 15 Plug-in contact 16 Circuit board 17 LED 18 Steel strip 19 End cap contact part 20 Snap-in protrusion 21 Recess 22 Snap-in cut-out 23 Fold-over region 23a Layer of the fold-over region 23 23b Layer of the fold-over region 23 24 Protrusion 25 Cavity 26 Groove-like receiver 31 Semiconductor lamp 32 Steel strip 33 Snap-in cut-out 34 Securing region 41 Semiconductor lamp 42 Steel strip 43 Snap-in cut-out 44 Material region 51 Semiconductor lamps 52 Circuit board 53 Snap-in cut-out 54 Tube d Longitudinal play E Insertion direction L Longitudinal direction