Source: https://patents.google.com/patent/EP1566846B1/en
Timestamp: 2019-10-22 20:31:35
Document Index: 192098583

Matched Legal Cases: ['art 2', 'art 2', 'art 2', 'art 8', 'art 2', 'art 2', 'art 2', 'art 2', 'art 2', 'art 8', 'art 22', 'art 22', 'art 2', 'art 2', 'art 2', 'art 2', 'art 12', 'art 2', 'art 2', 'art 2', 'arts 8', 'art 2', 'art 8', 'art 2', 'art 2', 'art 2', 'art 8', 'art 2', 'art 8', 'art 22', 'art 2', 'art 2', 'arts 8']

EP1566846B1 - Optoelectronic device - Google Patents
EP1566846B1
EP1566846B1 EP05011759.7A EP05011759A EP1566846B1 EP 1566846 B1 EP1566846 B1 EP 1566846B1 EP 05011759 A EP05011759 A EP 05011759A EP 1566846 B1 EP1566846 B1 EP 1566846B1
EP05011759.7A
EP1566846A3 (en
EP1566846A2 (en
2004-05-06 First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=7837261&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP1566846(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
2005-08-24 Publication of EP1566846A2 publication Critical patent/EP1566846A2/en
2009-08-19 Publication of EP1566846A3 publication Critical patent/EP1566846A3/en
2016-02-03 Publication of EP1566846B1 publication Critical patent/EP1566846B1/en
The invention relates to an optoelectronic component in which an optoelectronic chip is fastened on a chip carrier part of a leadframe by means of a heat-conducting connection means, the leadframe has a connection part arranged at a distance from the chip carrier part and electrically connected to an electrical contact of the chip and in which the chip and at least in each case a partial region of the chip carrier part and the connection part are surrounded by an enclosure such that for a printed circuit board assembly certain external connections of the chip carrier part and the connection part provided in the leadframe protrude from the enclosure or completely outside the enclosure lie. In particular, it relates to an optoelectronic component with an optoelectronic semiconductor chip, in particular with a high-performance light emitting diode chip (LED).
Such a device is for example from the European patent application EP 400 176 known. Herein, a so-called TOPLED is described in which a light-emitting semiconductor chip (LED chip) is mounted on a flat chip carrier part of a lead frame. The lead frame is composed of the chip carrier part and a at a distance to this, so electrically isolated from this arranged connecting part, each with an external terminal. The chip carrier part with the semiconductor chip, the connection part and subregions of the external connections are surrounded by an envelope, which consists of a radiation-impermeable base body with a recess and a radiation-permeable window part filling this recess. The chip carrier part and the connection part are surrounded by the base body or embedded in it in such a way that partial areas of the upper sides of the chip carrier part and the connection part with the flush the remaining bottom surface of the recess flush. The semiconductor chip is completely surrounded by the radiation-transmissive window part except for its underside, with which it rests on the chip carrier part. The recess and its inner surfaces are shaped and arranged such that it forms a substantially frusto-conical reflector for the radiation emitted by the semiconductor chip.
In the DE 19536454A1 An optoelectronic component is described in which two external terminals of the chip carrier part of the leadframe are widened with respect to the external terminals of the connection part in order to improve the heat dissipation from the semiconductor chip.
In the publication US 5,146,310 Two broad connections of the chip carrier part of a lead frame for heat dissipation to widely spaced contact points are described.
In the case of the known optoelectronic components described above, the semiconductor chip operates at high currents and thus at high power, as is the case, for example, with so-called power LEDs, due to insufficient heat dissipation from the semiconductor chip, to its intense heating. This heating often leads to impairment of the functionality of the semiconductor chip, such. As accelerated aging, breaking the semiconductor chip from the lead frame, canceling the bonding wires or destruction of the chip. The well-known widened external connections of the chip carrier part favor a delamination of the plastic from the lead frame, the z. B. can cause the penetration of moisture to the semiconductor chip.
The invention is therefore based on the object, the optoelectronic device of the type mentioned in such a way that an improved heat dissipation is ensured by the chip, without changing the housing dimensions and at the same time substantially without increasing the risk of delamination.
This object is achieved by a component having the features of claim 1.
Advantageous developments of the components according to the invention are the subject of the dependent claims.
In the device according to the invention it is provided that the chip carrier part has three separate, thermally conductively connected to the chip carrier part external terminals, which protrude at different, a distance from each other having points of the enclosure from this and which are shaped so that they are in on one of the Mounting the device provided circuit board mounted state of the device all at the same time rest on the terminal or circuit board. The resulting in the operation of the device in the chip heat is thus fed at three different points in the circuit board and distributed over a large area on this. As a result, a significantly improved heat dissipation is achieved by the optoelectronic chip.
In this embodiment of the component according to the invention, the external terminals of the chip carrier part run in a plan view of the lead frame, starting from the chip carrier part separated from each other substantially star-shaped outward. The heat dissipation points from the component to the printed circuit board are characterized by relatively large distances from each other, whereby a very large distribution of the thermal energy dissipated from the chip during operation of the device via the chip carrier part and its external connections is achieved on the printed circuit board.
Advantageously, the external terminals in the region in which they extend in a star-shaped outward direction, longitudinal central axes, of which two mutually adjacent each enclose an angle of about 90 °. In this arrangement, the plastic area between the terminals is maximum, causing the delamination z. B. is reduced in temperature fluctuations.
If a component with at least one first and one second optoelectronic chip is provided and if the chip carrier part has at least two external connections which protrude from it at different locations of the enclosure at a distance from one another, then the component does not belong to the invention but only serves for its purpose Explanation.
The lead frame here has at least two connection parts, each with an external connection, which also protrude laterally from the enclosure. Here, too, the external connections of the chip carrier part and the connection parts are preferably arranged substantially star-shaped as seen in plan view on the lead frame, whereby a maximum distance of the external terminals of the chip carrier part from each other is ensured. The derived during operation of the device via the chip carrier part and its external terminals from the chip thermal energy is thereby fed at relatively far apart points in the circuit board, so that here also a very good heat distribution on the circuit board is achieved.
In the latter component, the external terminals of the chip carrier part seen in plan view of the lead frame with respect to the chip carrier part can be arranged diagonally offset from one another. They then project on opposite side surfaces of a preferably substantially cuboid enclosure out of this. The connection parts are in this case arranged on different sides of the chip carrier part and their external connections also project on opposite side surfaces of the envelope out of this. In plan view of the lead frame, they are arranged opposite to the chip carrier part to the external terminals of the chip carrier part opposite to each other diagonally offset.
In order to further improve the heat dissipation from the chips, if necessary, the chip carrier part can also have more than two external connections, which in turn can be connected to different ones Distance from each other having points of the envelope sticking out of this. The number of these external connections can be further increased as needed depending on the permissible size of the device.
In an explanatory, non-inventive device that can be mounted on a circuit board, that during its operation emitted by the chip radiation is emitted substantially parallel to the circuit board (laterally emitting device), the chip carrier part at least two external terminals and the connection part on at least one external terminal, which protrude separately from one another on one and the same side surface of the enclosure from this. The external connection of the connection part is in this case preferably arranged between the two external connections of the chip carrier part.
In a particularly preferred development of the latter component, the external connection of the connection part is narrower than the two external connections of the chip carrier part. Of course, the external connections of the chip carrier part can optionally also be wider than the external connections of the connection parts in the case of the other abovementioned components according to the invention.
In a further development of the above-mentioned laterally emitting component, the chip carrier part is additionally heat-conductively connected to at least one cooling lug, which protrudes from the latter on another side surface of the sheathing than the connection parts. This cooling lug alone or a further cooling device thermally connected to this cooling lug ensures a further improved heat dissipation from the chip.
Further advantages and preferred embodiments will become apparent from the following in connection with the Figures 1 to 3b further explained examples. Show it:
FIG. 1a 1 is a schematic representation of a top view of an exemplary embodiment of a component according to the invention with a single optoelectronic chip,
FIG. 1b a schematic representation of a section through the embodiment of FIG. 1 along the line AA,
FIG. 2 1 is a schematic representation of a top view of an illustrative example of a component having at least two optoelectronic chips,
FIG. 3a a schematic representation of a side view of an illustrative example of a side emitting device and
FIG. 3b a schematic representation of a section through the illustrative example of FIG. 3 along the in FIG. 3 marked line AA.
In the figures, the same and equivalent components of the various examples are always provided with the same reference numerals.
In the device according to FIG. 1 it is a light-emitting diode device in which on a chip carrier part 2 of a lead frame (lead frame) 7, a light-emitting semiconductor chip 1 (LED chip) by means of a good heat-conducting connection means, for. B. is attached by means of a metallic solder. Three separate external terminals 4, 5, 6 extend from the chip carrier part 2 in three different directions to the outside. At a distance from the chip carrier part 2 with the external terminals 4, 5, 6, a connection part 8 is arranged with an external terminal 9, which by means of a bonding wire 16 with an electrical contact of the LED chip 1, z. B. is connected to the anode contact. A second contact metallization (cathode contact) of the LED chip 1 is located, for example, at its underside facing the chip carrier part 2 and is connected in an electrically conducting manner to the chip carrier part 2 by means of the connecting means that are also electrically conductive in this case. Of the Chip carrier part 2 with the external terminals 4, 5, 6 thus serves in this case both as a cathode connection and as a thermal connection for heat dissipation from the LED chip.
Is the cathode contact not, as in the above case, arranged on the underside of the chip 1, but z. B. at the top, this may be electrically connected by means of a bonding wire with the chip carrier part 2.
The chip carrier part 2, the connection part 8 and parts of their external terminals 4, 5, 6, 9 are enclosed by a substantially cuboid base body 10 of a sheath 3, which has a recess 11. The recess 11 has substantially the shape of a truncated cone and extends from a main frame 17 parallel to the main surface 17 of the body 10 to the lead frame 7, wherein the cross section of the recess 11 from the lead frame 7 to the main surface 17 of the body 10 increases. The LED chip 1 is located in the recess 11, which is provided with a radiation-permeable window part 22, preferably with a transparent plastic encapsulation. This window part 22 forms, together with the base body 10, a sheath 3 of the component. The external terminals 4, 5, 6, 9 protrude on opposite side surfaces 18,19 of the main body 10 out of this. Initially, they extend apart in a star-shaped manner within the base body 10 starting from the chip carrier part 2 and buckle off in the further course, so that they penetrate the side surfaces 18, 19 vertically.
The chip carrier part 2 is preferably located completely within the bottom surface of the recess 11.
The external terminals 4, 5, 6, 9 have, in the region in which they extend in a star-shaped manner outwards, longitudinal central axes 23, 24, 25, of which two mutually adjacent angles enclose an angle of approximately 90 °.
The external terminals 4, 5, 6, 9 are outside of the main body 10 initially bent toward the second main surface 20 of the main body 10 opposite the first main surface 17 and laterally below the main body 10 toward the center thereof. But you can also, as in FIG. 1b indicated by dashed lines, bent to swing-shaped connection stubs. This, too, is a form of external electrical connections which is conventional in the surface mount technique. These types of external surface mount device (SMD) terminals are well known in the art and will not be discussed further herein.
The external terminals are thus shaped so that they all rest simultaneously on the terminal or circuit board in mounted on a provided for mounting the component circuit board state of the device.
The inner surfaces of the recess 11 form a reflector for the emitted from the LED chip 1 during operation of the device radiation. They are optionally coated with a reflection-enhancing material. Alternatively, the main body may consist of a reflection-enhancing material.
In the illustrative example of FIG. 2 are in contrast to the embodiment of FIGS. 1a and 1b On a chip carrier part 2 of a lead frame 7, two differently colored LED chips 1, 13 fixed by means of a thermally and electrically conductive connection means. On opposite sides of the chip carrier part 2, at a distance therefrom, a first 8 and a second connecting part 12 are arranged, each of which has an external terminal 9,14. These external terminals 9,14 parallel to each other offset from each other, extend, as viewed from the chip carrier part 2, in opposite directions and protrude on opposite side surfaces 18,19 of the body 10 out of this. They are electrically connected by means of bonding wires 16 with the anode contacts of the LED chips 1.13.
The chip carrier part 2 has two external connections 4, 5 which, starting from the chip carrier part 2, also extend parallel to one another in mutually opposite directions parallel to the external connections 9, 14 of the connection parts 8, 12 and on opposite side surfaces 18, 19 of the main body 10 protrude from this.
As in the embodiment of FIGS. 1a and 1b , the radiopaque base body 10 has a frusto-conical recess 11 provided with a transparent window portion 22. The LED chips 1,13 are located in this recess 11.
The external terminals 4,5,9,14 protrude on opposite side surfaces 18,19 of the body 10 out of this. They are outside of the body 10 analogous to the embodiment according to FIGS. 1a and 1b shaped.
In the examples described above, the envelope 3 and the external terminals 4, 5, 6, 9, 14 are each designed such that, during operation of the component, the radiation emitted by the LED chip (s) is substantially perpendicular to the mounting surface of a is emitted for mounting the device provided circuit board.
In the illustrative example of Figure 3a and 3b it is a so-called side emitting LED device. This type of component is already explained in the general part of the description. The casing 3 and the external terminals 4, 5 and 9 of the chip carrier part 2 or of the connection part 8 are formed in this component in such a way that they have a side surface 20 of the base body 10 can be attached to the mounting surface of a circuit board out on this.
For this purpose, a lead frame 7 has a chip carrier part 2 which has at least two external connections 4, 5. These external terminals 4, 5 extend first from the chip carrier part 2, on which an LED chip 1 is fastened by means of a thermally and electrically conductive connection means, in essentially opposite directions to the outside. In the further course they bend in the same direction, so that they then run parallel to each other in the same direction. Between the two external terminals 4, 5 of the chip carrier part 2, there is a connection part 8 with an external connection 9, which runs in the same direction as the latter parallel to the two external connections 4, 5 of the chip carrier part.
The chip carrier part 2, its external terminals 4, 5, the connection part 8 and its external connection 9 are enclosed analogously to the two examples described above with a radiopaque base body 10 which has a frusto-conical recess 11 in which the LED chip 1 is arranged , The recess 11 is also provided here with a radiation-permeable window part 22, which preferably consists of a radiation-permeable plastic. The external terminals 4,5,9 protrude on one and the same side surface 18 of the main body 10 out of this, are bent outside the main body 10 down toward the back of the body 10 and are in the course along the back 21 of the body 10 to its middle bent. The remote from the side surface 18 of the base body 10 outer surfaces of the external terminals 4,5,9 form a support surface of the device for mounting on a circuit board.
For additional cooling of the LED chip 1, the chip carrier part 2 with a cooling lug 15 may have (in the FIGS. 3a and 3b dashed lines drawn). This protrudes on one of the side surface 18, from which protrude the external terminals 4,5,9, opposite side surface 19 of the main body 10 out of this and is outside the main body 10 to the rear side 21 out bent so that they on the side surface 19th rests. Optionally, further cooling devices can be connected thermally to this cooling lug 15.
In all the examples described above, the external terminals of the chip carrier part 2 are wider than the external terminals of the connecting parts 8, 12. Thus, with substantially unchanged housing dimensions, a further improved heat dissipation from the LED chip 1 can be achieved. But the external terminals 4,5,6,9,12 can also all have the same width.
In order to achieve a further improvement of the heat dissipation from the LED chip, particularly large solder pads are provided on a circuit board provided for mounting the component. These are also arranged in a star shape and can thus distribute the dissipated heat from the LED chip over a large area on the circuit board. The leadframes of the components according to the invention conduct the heat in a star shape from the LED chip to the outside of the housing. As a result, the heat is fed into the board at points far away from each other. On the board are preferably around each solder pad large, for example made of copper metallizations, which distribute the heat on the circuit board. The thermal resistance of the housing according to the invention is significantly reduced compared to the thermal resistance of conventional LED housings.
The housings for LED chips described above are housings for optoelectronic components known in semiconductor technology. The special forms, the materials used and manufacturing processes are therefore not explained in more detail here.
The description of the invention annex of the embodiment is of course not to be understood as limiting the invention to this example.
Optoelectronic surface-mountable component, in which an optoelectronic chip (1) is fixed on a chip carrier part (2), forming a first main area (17), of a leadframe (7) by means of a connecting means having good thermal conductivity, in which the leadframe (7) has a connection part (8) which is arranged at a distance from the chip carrier part (2) and is electrically conductively connected to an electrical contact of the optoelectronic chip (7), and in which the optoelectronic chip (1) and a part of the leadframe (7) are surrounded by an encapsulation (3) forming a base body (10), the base body (10) having an outwardly facing second main area (20) opposite to the first main area (17), and four external connections (4, 5, 6, 9) of the chip carrier part (2) and of the connection part (8) which are provided in the leadframe (7) project from the encapsulation (3) and are shaped there in such a way that, in the state of the component mounted on a connection board or printed circuit board provided for the mounting of the component, said external connections all bear simultaneously on the connection board or printed circuit board,
wherein three of the external connections (4, 5, 6) are formed by heat-conducting connections (4, 5, 6) which are thermally conductively connected to the chip carrier part (2) and which, as seen from the chip carrier part, run outwards within the encapsulation separately from one another essentially in a starshaped manner and, at different mutually spaced apart locations at two opposite side areas of the encapsulation (3), project from the latter in such a way that heat that arises in the chip during the operation of the component is fed into the connection board or printed circuit board at three different points and is distributed over a large area on said board.
wherein the encapsulation (3) is composed completely of a radiation-transmissive material.
Optoelectronic component according to either of Claims 1 and 2,
wherein provision is made of a recess (11) in the encapsulation (3) forming the base body (10), in which a radiation-transmissive window part (12) is arranged, wherein the chip carrier part (2) is partially encapsulated by the radiation-opaque base body (10) and wherein the chip (1) is arranged in the recess (11).
Optoelectronic component according to Claim 3,
wherein the recess (11) is formed such that its profile is expanded in cross section outwards from within the encapsulation (3).
wherein the inner area(s) of the recess (11) is/are formed as a reflector for the radiation emitted and/or received by the chip (1).
EP05011759.7A 1997-07-29 1998-07-27 Optoelectronic device Expired - Lifetime EP1566846B1 (en)
EP10181078.6A EP2267798B1 (en) 1997-07-29 1998-07-27 Optoelectronic device
EP10181067A EP2267797A1 (en) 1997-07-29 1998-07-27 Optoelectronic device
EP98947353A Division EP1004145B1 (en) 1997-07-29 1998-07-27 Optoelectronic component
EP10181067A Division-Into EP2267797A1 (en) 1997-07-29 1998-07-27 Optoelectronic device
EP10181078.6A Division-Into EP2267798B1 (en) 1997-07-29 1998-07-27 Optoelectronic device
EP10181078.6A Division EP2267798B1 (en) 1997-07-29 1998-07-27 Optoelectronic device
EP1566846A2 EP1566846A2 (en) 2005-08-24
EP1566846A3 EP1566846A3 (en) 2009-08-19
EP1566846B1 true EP1566846B1 (en) 2016-02-03
EP2628194B8 (en) 2010-10-12 2018-08-29 Lumileds Holding B.V. Method of manufacturing a light emitting device
DE202012009560U1 (en) 2012-10-08 2014-01-09 Oechsler Aktiengesellschaft Event detector and medication donor with such event detector
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