Lighting unit for a household appliance

Abstract

A lighting unit for a household appliance, the lighting unit has a printed circuit board having a light-emitting means arranged on the printed circuit board, and a base for receiving the printed circuit board. The printed circuit board is arranged on a metallic holding part such that good thermally conductive contact is provided between the printed circuit board and the holding part, and the holding part is fastened on the base in such a way that good heat transfer is provided from the holding part to the base.

Claims

1. A lighting unit that is configured to be used for a working area in a household appliance, the lighting unit comprising: a printed circuit board comprising a light-emitting means arranged on the printed circuit board, and a base for receiving the printed circuit board, wherein the printed circuit board is arranged on a holding part, the holding part comprising an elongate bar element having a length and a predetermined width extending in a longitudinal axis direction from one end to another end of the bar element, a hook-shaped pocket having a width is integrally formed at the one end of the bar element, the hook-shaped pocket comprises a single arc portion connecting opposed portions in the length of the bar element such that the opposed portions form an axis in the hook-shaped pocket, wherein the entire width of the hook-shaped pocket is equal to or less than the predetermined width of the bar element, and the axis in the hook-shaped pocket is at an angle relative to the longitudinal axis direction of the bar element and one of a plug-type connection and a soldered joint is integrally formed at the another end of the bar element for connection to an electrical supply voltage, wherein the printed circuit board is plugged into the hooked-shaped pocket to be fastened to the holding part and to make electrical contact with the electrical supply voltage such that thermally conductive contact is provided between the printed circuit board and the holding part, and the holding part is fastened on the base by means of being clamped in on the base, in such a way that heat transfer is provided from the holding part to the base.

2. The lighting unit as claimed in claim 1, wherein two holding parts are used for supplying an electrical voltage from the electrical supply voltage to the light-emitting means arranged on the printed circuit board.

3. The lighting unit as claimed in claim 1, wherein a cover is positioned onto the base in such a way that the base and the cover form a housing for the lighting unit.

4. The lighting unit as claimed in claim 1, wherein the light-emitting means comprises a light-emitting diode, and the light-emitting diode is soldered onto the printed circuit board as an SMD (surface mounted device) component.

5. The lighting unit as claimed in claim 1, wherein two contact pads for making electrical contact by means of the holding part are provided on the printed circuit board.

6. The lighting unit as claimed in claim 1, wherein the holding part is in the form of a stamped or bent element.

7. The lighting unit as claimed in claim 1, wherein the hook-shaped pocket is integrally formed at the one end of the bar element such that the axis in the hook-shaped pocket is perpendicular to the longitudinal axis direction of the bar element.

8. The lighting unit as claimed in claim 1, wherein the holding part consists of metal, and at least one of the base, a cover and a protective cap consist of polymer.

9. The lighting unit as claimed in claim 8, wherein the polymer is a thermoplastic polymer.

10. The lighting unit as claimed in claim 1, wherein the electrical contact is made with the printed circuit board by means of two holding parts.

11. The lighting unit as claimed in claim 1, wherein the printed circuit board is fastened by means of two holding parts.

12. The lighting unit as claimed in claim 10, wherein the two holding parts have a substantially identical configuration.

13. The lighting unit as claimed in claim 11, wherein the two holding parts have a substantially identical configuration.

14. The lighting unit as claimed in claim 1, wherein a transparent protective cap is positioned on a front side of the base facing the printed circuit board.

15. The lighting unit as claimed in claim 5, wherein the printed circuit board has an area having a size which substantially corresponds to the sum of areas of the light-emitting means and the contact pads in such a way that the area of the printed circuit board is only insubstantially greater than that of the light-emitting means.

16. The lighting unit as claimed in claim 1, wherein an emission direction for light from the light-emitting means is arranged on the printed circuit board, such that the emission direction of the light from the light-emitting means is emitted out of the lighting unit at the angle of the axis in the hook-shaped pocket relative to the longitudinal axis direction of the bar element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention with various developments and configurations are illustrated in the drawings and will be described in more detail below.

(2) FIG. 1 shows a lighting unit in a perspective view;

(3) FIG. 2 shows the lighting unit shown in FIG. 1 in an exploded illustration; and

(4) FIG. 3 shows a lighting unit corresponding to a further embodiment.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIG. 1 shows a lighting unit 1 for a household appliance. The lighting unit 1 is used, for example, as a drum lighting unit for the drum of a washing machine, a tumble dryer or the like or as a lighting unit for another working area in a household appliance. The lighting unit 1 has a housing 2, which comprises a base 3 and a cover 4. In this case, the cover 4 is positioned onto the base 3, as can be seen from FIG. 2. As can further be seen from FIG. 2, a printed circuit board 5 is located in the housing 2, wherein a light-emitting means 6 comprising a light-emitting diode (LED) is arranged on the printed circuit board 5. A cutout 7 for receiving the printed circuit board 5 is located in the front side in the base 3. Furthermore, a metallic holding part 8 is located in the housing 2. The printed circuit board 5 is arranged on the metallic holding part 8 in such a way that good thermally conductive contact is provided between the printed circuit board 5 and the holding part 8. Furthermore, the holding part 8 is fastened on the base 3, to be precise by means of the holding part 8 being clamped in in a corresponding receptacle 16 in the base 3, in such a way that good heat transfer is provided from the holding part 8 to the base 3. Thus, the lost heat produced in the light-emitting means 6 can be dissipated in a simple manner via the printed circuit board 5, the holding part 8 and the base 3, acting as cooling area, to the surrounding environment or to the household appliance housing in which the lighting unit 1 is installed. If desired, in addition a heat sink can also be arranged on the base 3 for further improving heat dissipation, but this is not shown in any further detail.

(6) The holding part 8 has a hook-shaped pocket 9 at one end, into which pocket the printed circuit board 5 is plugged for fastening purposes. The holding part 8 at the same time is also used for supplying the electrical voltage for the light-emitting means 6. For this, the holding part 8 has, at the pocket 9, a contact pin 10, which, when the printed circuit board 5 is plugged into the pocket 9, rests on a corresponding contact pad 17 on the printed circuit board 5 for making electrical contact with the light-emitting means 6. A plug-type connection and/or soldered joint 11 for the electrical voltage supply is integrally formed at the other end of the holding part 8. In order to complete the voltage supply, the contact is made with the printed circuit board 5 by means of two holding parts 8, 8, which have a substantially identical configuration. A plug 12, which is used for connection of the lighting unit 1 to the supply voltage, can be plugged onto the plug-type connections and/or soldered joints 11 on the housing 2. The two holding parts 8, 8 also effect secure fastening of the printed circuit board 5 in the base 3. The holding part 8, 8, which comprises an elongate bar element 18, together with the pocket 9 integrally formed at the one end of the bar element 18, the contact pin 10 and the plug-type connection and/or soldered joint 11 integrally formed at the other end of the bar element 18 can be produced as a stamped and/or bent element.

(7) The light-emitting diode 6 can be in the form of an SMD (surface mounted device) component. In this case, the light-emitting diode 6 is soldered onto the printed circuit board 5 using the SMD method. Two contact pads 17 for making electrical contact by means of the holding parts 8, 8 are provided on the printed circuit board 5, wherein only one contact pad 17 is shown in FIG. 2, however. The printed circuit board 5 then has a basic area with a size which substantially corresponds to the areas of the light-emitting diode 6 and the contact pads 17. As can be seen from FIG. 2, the basic area of the printed circuit board 5 is therefore only insubstantially larger than that of the light-emitting diode 6, which enables a very compact configuration of the lighting unit 1.

(8) As can be seen from FIG. 2, the printed circuit board 5 is arranged substantially perpendicular to the longitudinal axis of the holding part 8, 8 or the bar element 18, wherein the longitudinal axis is denoted by the directional arrow 15. In another embodiment which is shown in FIG. 3, the printed circuit board 5 is arranged at an angle to the longitudinal axis of the holding part 8, 8 or the bar element 18. This configuration can be expedient for particular lighting unit situations in the household appliance. In this case, the cutout 7 in the base is also provided with a corresponding bevel, and the pocket 9 is arranged on the holding part 8, 8 at an angle to the longitudinal axis 15 of the holding part 8, 8. In the embodiment shown in FIG. 3, moreover, the plug-type connection is not bent back at the holding part 8, 8 but runs along the longitudinal axis 15 of the bar element 18. In this case, the plug 12 can then be plugged onto the rear side of the housing 2, while in the embodiment shown in FIG. 2, the plug 12 can be plugged onto the housing 2 from below.

(9) As shown in FIG. 2, a transparent protective cap 13 is positioned on the front side of the housing 2 which faces the printed circuit board 5. In the embodiment shown in FIG. 3, the protective cap 13 and/or the cover 4 are provided with beveling 14 corresponding to the angling of the printed circuit board 5. As already mentioned, the holding part 8, 8 consists of metal, to be precise of a metal with good electrical conductivity and good thermal conductivity. For example, the metal may be copper, copper-beryllium, bronze, brass or the like. The base 3, the cover 4 and the protective cap 13 consist of a polymer. Preferably, a thermoplastic polymer is used for this, with the result that these parts can be produced by means of injection molding in an inexpensive manner.

(10) The invention is not restricted to the exemplary embodiments described and illustrated. Instead, it also includes all developments by a person skilled in the art in the context of the invention defined by the patent claims. Thus, such a lighting unit 1 can be used not only in household appliances but also in other appliances with a lighting unit.

LIST OF REFERENCE SYMBOLS

(11) 1: Lighting unit 2: Housing 3: Base 4: Cover 5: Printed circuit board 6: Light-emitting means/light-emitting diode 7: Cutout (in base) 8, 8: Holding part 9: Pocket 10: Contact pin 11: Plug-in connection and/or soldered joint 12: Plug 13: Protective cap 14: Beveling 15: Directional arrow (longitudinal axis of holding part) 16: Receptacle (in base) 17: Contact pad (on printed circuit board) 18: Bar element