Semiconductor lamp

Abstract

A semiconductor lamp (1) has at least one semiconductor light source (8) arranged on a front face (7) of a substrate (6) and a driver circuit (11) for activating the at least one semiconductor light source (8), at least part of the driver circuit (11) being secured on a rear face (10) of the substrate (6), facing away from the at least one semiconductor light source (8). The invention can be used, in particular, for retrofit lamps, in particular incandescent- or halogen retrofit lamps.

Claims

1. A semiconductor lamp, comprising: at least one semiconductor light source arranged on a front side of a substrate; a driver circuit for controlling the at least one semiconductor light source, wherein at least part of the driver circuit is attached to a back side of the substrate facing away from the at least one semiconductor light source; a cooling body lying superficially on the front side of the substrate, wherein the cooling body has at least one recess for the at least one semiconductor light source, and wherein the cooling body is a dish-like cooling body with a plate-like base and a side edge protruding therefrom at an angle; and at least one optical element disposed over the cooling body and having legs protruding to a rear, wherein each leg extends through a respective recess in the plate-like base of the cooling body as far as the substrate such that material of the cooling body physically intervenes between the legs and the at least one semiconductor light source.

2. The semiconductor lamp according to claim 1, wherein the at least one recess for the at least one semiconductor light source is made in the plate-like base.

3. The semiconductor lamp according to claim 1, wherein the cooling body is attached to the substrate by means of an adhesive heat-conductive layer.

4. The semiconductor lamp according to claim 1, wherein the substrate is accommodated in a housing.

5. The semiconductor lamp according to claim 4, wherein the housing has a socket region on a back of the housing and is open at a front of the housing.

6. The semiconductor lamp according to claim 4, wherein the side edge of the cooling body lies superficially on an inside of the housing.

7. The semiconductor lamp according to claim 4, wherein the driver circuit in the housing is surrounded by potting compound.

8. The semiconductor lamp according to claim 1, wherein the substrate has a conductive structuring on one side only, and components attached on the other side of the substrate are electrically connected to the conductive structuring via electrically conductive passages through the substrate.

9. The semiconductor lamp according to claim 1, wherein the semiconductor lamp is a retrofit lamp.

10. The semiconductor lamp according to claim 1, wherein the plate-like base of the cooling body has different recesses for the at least one semiconductor light source and for the legs protruding to the rear.

11. The semiconductor lamp according to claim 1, wherein the at least one recess for the at least one semiconductor light source and the recesses in the plate-like base of the cooling body through which each leg extends are co-planar.

12. The semiconductor lamp according to claim 1, wherein the cooling body further has at least one recess for protrusions on the front side of the substrate from conductive passages.

13. The semiconductor lamp according to claim 12, wherein material of the cooling body physically intervenes between the protrusions on the front side of the substrate from conductive passages and the at least one semiconductor light source.

14. The semiconductor lamp according to claim 12, wherein the at least one recess for the at least one semiconductor light source and the at least one recess for protrusions on the front side of the substrate from conductive passages are co-planar.

15. The semiconductor lamp according to claim 1, wherein only the legs of the at least one optical element are disposed within the cooling body.

16. The semiconductor lamp according to claim 15, wherein a main body portion of the at least one optical element is external to the cooling body.

17. The semiconductor lamp according to claim 16, wherein the main body portion of the at least one optical element is not in physical contact with the cooling body.

18. The semiconductor lamp according to claim 1, wherein the at least one optical element is further configured to reside on a shoulder of a housing of the semiconductor lamp.

19. The semiconductor lamp according to claim 1, wherein the cooling body is adhered to the front side of the substrate.

20. The semiconductor lamp according to claim 1, wherein the at least one optical element is disposed over of the cooling body such that an air gap separates a rear side of the at least one optical element and a front side of the cooling body.

Description

(1) The properties, features and advantages described above of this invention and the manner in which these are achieved will become clearer and easier to understand in connection with the diagrammatic description below of an exemplary embodiment which is explained in more detail in connection with the drawings. For the sake of clarity, the same or equivalent elements carry the same reference numerals.

(2) FIG. 1 shows, in an exploded depiction in an oblique view, a semiconductor lamp according to a first exemplary embodiment;

(3) FIG. 2 shows, in an exploded depiction in an oblique view, selected parts of the semiconductor lamp according to the first exemplary embodiment;

(4) FIG. 3 shows, as a partial section depiction in an oblique view, the assembled semiconductor lamp according to the first exemplary embodiment; and

(5) FIG. 4 shows, as a partial section depiction in an oblique view, an extract from the semiconductor lamp according to the first exemplary embodiment.

(6) FIG. 1 shows, as an exploded depiction in an oblique view, a semiconductor lamp 1 in the form of a halogen retrofit lamp. The semiconductor lamp 1 has a housing 2 with a cup-like base form with a socket region 3 on its rear end. The housing 2 is here shown partially cut away. The semiconductor lamp 1 has a longitudinal axis A running from the back (the socket region 3) to the front (a light emission region).

(7) The socket region 3 serves for mechanical fixing of semiconductor lamp 1 in a conventional bi-pin bulb fitting (not shown), e.g. for halogen lamps. For further mechanical fixing and the electrical connection of the semiconductor lamp 1, two metallic connecting pins 4 protrude to the rear from a rear face of the socket region 3, and together with the socket region 3 form a bi-pin socket of the semiconductor lamp 1, e.g. of the type GU, e.g. GU10.

(8) The housing 2 is open at the front, wherein a substrate 6 can be inserted through a front opening 5. The substrate 6 is here configured as a circular FR4 or CEM substrate as shown more precisely in FIG. 2. Several semiconductor light sources in the form of LED chips 8 are arranged on the front 7 of the substrate 6. The LED chips 8 are connected together via contact fields 9 present on the front 7. The contact fields 9 consist of metallic layers, e.g. of copper, and together form a conductive structure.

(9) Components 11 of the driver circuit for controlling the LED chips 8 are attached to a back 10 of the substrate 6. The substrate 6 is thus a common substrate for both the LED chips 8 and for the components 11 of the driver circuit. The front 7 and the back 10 of the substrate 6 are in principle electrically isolated from each other. An electrical connection of the components 11 of the driver circuit and the LED chips 8 is achieved by at least one electrically conductive passage (not shown) between the front 7 and the back 10 of the substrate 6.

(10) In a variant, the substrate 6 is provided with a respective conductive structure on both sides, each of which may have one or more conductor tracks and/or contact fields. The conductive structure here has four contact fields 9 which connect the LED chips 8, physically arranged in a ring, electrically in series. In a particularly economic variant, the substrate 6 has a conductive structure only on one side, e.g. here on the front 7. An electrical connection of the components 11 on the back 10 to the conductive structure on the front 7 may then be implemented e.g. by means of the conductive passage(s). This may e.g. be achieved in that the components 11 are components configured for through-hole mounting, for example in that they have connecting pins (not shown) guided through the substrate 6.

(11) A cooling body 12 with a dish-like base form lies superficially on the front 7 of the substrate 6, as shown more precisely in FIG. 2. The cooling body 12 has a plate-like base 13 and a side edge 14 extending from the rim to the rear, with multiple interruptions. The base 13 has recesses 15 for the LED chips 8 and further recesses 16, e.g. for the protrusions on the front 7 of the substrate 6 created by the conductive passages. Also, recesses 23 for legs 22 are present in the base 13, as will be explained in more detail below.

(12) The cooling body 12 is glued to the substrate 6 by means of an adhesive heat-conductive layer 17. This ensures a strong fixing with simultaneously low thermal resistance. The heat-conductive layer 17 has holes or recesses 15a, 16a or 23a similar to the recesses 15, 16 and 23 of the base 13, as shown in more detail in FIG. 2. The heat-conductive layers 17 may e.g. be present as a heat-conduction film. As an alternative to a TIM material, a so-called gap filler may be used, e.g. a gap pad, so that recesses 16a for protrusions caused by conductive passages may be omitted without overly increasing a heat resistance.

(13) In order to improve a mechanical and thermal connection of the components 11 to the housing 2, the housing 2 is filled up to the substrate 6 with a potting compound 20, which also surrounds the components 11.

(14) The cooling body 12 on the front is covered by an optical element in the form of a lens element 21. The lens element 21 is a common lens for the LED chips 8, and on the back has several (here three) protruding contact regions in the form of pin-like feet or legs 22, as shown in more detail in FIG. 2. The legs 22 lead through recesses 23 in the base 13 of the cooling body 12 and similar recesses 23a in the heat-conductive layer 17. They contact the front 7 of the substrate 6 and act as positioning aids, in particular as spacers.

(15) The lens element 21 is pressed backward by means of a retaining ring 24 so that it does not detach from the substrate 6. For this, the retaining ring 24 is arranged in front of the lens element 21 and can engage with an inside of the housing 2 via catch hooks 25.

(16) FIG. 3 shows the assembled semiconductor lamp 1 with a housing 2 cut away at the side. FIG. 4 shows the assembled semiconductor lamp 1 is a section view through a front region at the level of the substrate 6. The potting compound 20 is not shown on these two figures.

(17) The side edge 14 of the cooling body 12 lies with its outside superficially on the housing 2 and thus allows an effective heat transmission to the housing 2. Also, the cooling body 12 may be held thus clamped in the housing 2.

(18) The substrate 6 lies with an edge region of its back 10 on retaining tabs 26 which protrude forward from an inside of the housing 2.

(19) The retaining ring 24 at the front terminates practically flush with the housing 2.

(20) Above each LED chip 8, the lens element 21 has a rearward protruding, lens-like light collection region 27. The light collection region 27 may for example have a recess with a convex base above each respective LED chip 8. In this way, practically all the light emitted from an LED chip 8 is captured and conducted forward over a wide area in the lens element 21. On its generally flat front, the lens element 21 has a field 28 of micro-lenses which further even out the light emission. The micro-lenses may in particular be formed convex e.g. spherical, aspherical or pad-like.

(21) This semiconductor lamp 1 has only one fitting direction, which keeps the production complexity of the entire platform at a low level.

(22) On operation of the semiconductor lamp 1, the driver circuit with the driver components 11 is supplied with an electrical power signal (e.g. a network voltage) via the electrical connection pins 4. The driver circuit converts the electrical power signal into an electrical operating signal suitable for operation of the series-connected LED chips 8. This may e.g. be cyclic and/or adjustable in relation to its current intensity. The operating signal may allow a dimmed operation of the LED chips 8. Since at least some of the connecting pins of the driver components 11 of the driver circuit are guided through the substrate 6 and electrically connected to the contact fields 9 present there, the operating signal may simply be supplied to the LED chips 8. The light then emitted by the LED chips 8 passes through the recesses 15 of the base 13 of the cooling body 12 and into the respective light collection regions 27 of the lens element 21. The light coupled into the rear of the lens element 21 is then emitted from the semiconductor lamp 1 at the front through the field 28 of micro-lenses. Waste heat generated by the LED chips 8 is transmitted to the base 13 of the cooling body 12 and then above all from its side edge 14 to the housing 2 and emitted outward through the housing 2.

(23) Although the invention has been illustrated in detail and described with reference to the exemplary embodiment shown, the invention is not restricted thereto and other variations may be derived by the person skilled in the art without leaving the scope of protection of the invention.

(24) In general, the terms one or a etc. mean an individual or a plurality, in particular 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 precisely one etc.

(25) Also, a figure given may mean precisely the given figure and also include a usual tolerance range, as long as this is not explicitly excluded.

REFERENCE NUMERALS

(26) 1 Semiconductor lamp 2 Housing 3 Socket region 4 Connecting pin 5 Front opening 6 Substrate 7 Front 8 LED chip 9 Contact field 10 Back 11 Component 12 Cooling body 13 Base 14 Side edge 15 Recess 15a Recess 16 Recess 16a Recess 17 Heat-conductive layer 20 Potting compound 21 Lens element 22 Leg 23 Recess 23a Recess 24 Retaining ring 25 Catch hook 26 Retaining tab 27 Light collection region 28 Field of micro-lenses A Longitudinal axis