DE102011076425A1 - Semiconductor lighting device and method for producing a semiconductor lighting device - Google Patents

Abstract

The semiconductor lighting device (F) has at least one semiconductor light source (9) which is mounted on at least one end face (2, 3) of a thermally highly conductive, plate-shaped heat sink element (1), wherein the at least one semiconductor light source (9) of exactly one Heat sink element (1) is worn. The method is used to produce a semiconductor lighting device (F), wherein a plurality of electrically conductive, plate-shaped heat sink elements (1) are assembled to form a stack (6); on at least one Bestückoberfläche (7) of the stack (6), which results from adjacent end faces (2, 3) of the heat sink elements (1), an electrical insulating layer (8) is applied; on the electrical insulating layer (8) at least one conductor track (10) is applied; the at least one Bestückoberfläche (7) is equipped with at least one semiconductor light source (9); and the at least one semiconductor light source (9) is electrically contacted with the at least one conductor track (10).

Description

The invention relates to a semiconductor light-emitting device, comprising at least one semiconductor light source, which is mounted on at least one end face of a plate-shaped heat sink element. Such a semiconductor light-emitting device can be used in particular as a retrofit lamp, e.g. as a substitute for a fluorescent tube. The invention further relates to a method for producing such a semiconductor light-emitting device.

US 7,878,686 B2 discloses a lighting device with a light source in the form of a packaged light emitting diode and with a heat sink, which has a plurality of plate-shaped elements, which consist of a thermally conductive material. The plural plate-shaped members are stacked on each other and allow formation of a gap between them at one end portion. The light source is attached to a side surface on the plurality of stacked plate-shaped members.

It is the object of the present invention to provide an improved lighting device using at least one plate-shaped heat sink element.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The semiconductor lighting device has at least one semiconductor light source which is mounted on at least one end face of a thermally highly conductive, plate-shaped heat sink element, wherein the at least one semiconductor light source is supported by exactly one heat sink element.

This semiconductor light-emitting device has the advantages that it is scalable by varying the number of plate-shaped heat sink elements used simple and basically unlimited in their light intensity. In contrast to a support of the semiconductor light source on a plurality of heat sink elements, no mechanical stresses occur on the semiconductor light source due to the heat sink element. In addition, a single plate-shaped heat sink element can be produced and handled more easily than a plurality of correspondingly narrower plate-shaped heat sink elements, in particular in the case of semiconductor light sources with a small contact surface, in particular LED chips.

A plate-shaped heat sink element can be understood in particular to be a heat sink element which has a considerably greater extent with respect to its length and its height than with respect to its width. Under a front page can then be understood in particular a page which is extended in width, so it is very narrow.

The at least one semiconductor light source may be arranged on one or more end faces. The at least one end face thus provides a support surface for the at least one semiconductor light source.

A thermally highly conductive heat sink element can be understood in particular to be a heat sink element which or its material has a thermal conductivity of more than 2 W / (m · K), in particular more than 10 W / (m · K).

The plate-shaped heat sink element may in particular be an electrically conductive material, in particular metal, since electrically conductive, in particular metallic, bodies are generally thermally highly conductive. In particular, metallic bodies can be produced inexpensively and simply shaped and reworked. In addition, they can perform an electrical function, e.g. as a mass.

However, the material of the heat sink element is not limited to this and may include thermally conductive plastic and thermally conductive ceramics. In particular, the material of the heat sink element may consist of a thermally good, but not electrically conductive material, in particular ceramic, for example AlN.

It is an embodiment that the at least one semiconductor light source rests directly on the heat sink element. This advantageously enables a particularly effective heat transfer from the semiconductor light source to the heat sink element. It is a development that this heat sink element is thermally highly conductive, but is electrically non-conductive, e.g. a ceramic plate made of AlN.

It is another development that the heat sink element is electrically conductive and the at least one semiconductor light source is designed to be electrically insulated from the heat sink element. Thus, a wide variety, including electrically conductive, materials may be used for the heat sink element, e.g. a metal, and yet in this case too, a reduction in thermal flux from the semiconductor light source to the heat sink element due to an intervening electrical insulation layer, which typically has a low thermal conductivity of less than 1 W / (m · K), can be avoided.

It is still a further development that contact surfaces of the semiconductor light source are arranged overhead (facing away from the heat sink element) are what facilitates contact, in particular by means of wire bonding. This applies in particular to a semiconductor light source which is electrically insulated from the heat sink element.

It is yet an embodiment that the heat sink element is electrically conductive and between the at least one semiconductor light source and the heat sink element, an electrically insulating insulating layer is present. This results in the advantage that a wide variety of semiconductor light sources can be used, in particular with regard to their electrical connection type.

It is a further embodiment that the at least one plate-shaped heat sink element is made of aluminum (including an alloy thereof), since aluminum is inexpensive, corrosion resistant, highly thermally conductive, and lightweight. However, other metals and their alloys are conceivable in particular, for example comprising iron and / or copper.

Preferably, the at least one semiconductor light source comprises at least one light-emitting diode. If several LEDs are present, they can be lit in the same color or in different colors. A color may be monochrome (e.g., red, green, blue, etc.) or multichrome (e.g., white). The light emitted by the at least one light-emitting diode can also be an infrared light (IR LED) or an ultraviolet light (UV LED). Several light emitting diodes can produce a mixed light; e.g. a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor (conversion LED). The phosphor can alternatively or additionally be arranged remotely from the light-emitting diode ("remote phosphor"). The at least one light-emitting diode can be in the form of at least one individually housed light-emitting diode or in the form of at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, e.g. at least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic light emitting diodes, e.g. based on InGaN or AlInGaP, organic LEDs (OLEDs, for example polymer OLEDs) can generally also be used. Alternatively, the at least one semiconductor light source may be e.g. have at least one diode laser.

It is a particularly preferred embodiment that the at least one semiconductor light source is present in the form of at least one LED chip. An LED chip is particularly small (with a typical width of about 0.25 mm), so that results in a high packing density of the LED chips. This in turn allows a use of particularly narrow heat sink elements and consequently a high luminance of the semiconductor light-emitting device. In addition, due to the missing housing, a heat dissipation from the LED chip is particularly high, in particular through a bearing surface of the LED chip.

The at least one LED chip may in particular be glued or soldered. The gluing is preferably carried out by means of a good thermal conductivity adhesive, e.g. a thermal grease, a heat-conductive adhesive film, etc.

It is a further development that the at least one LED chip subsequently encapsulated, in particular subsequently potted, is. This improves protection of the LED chip. Subsequent encapsulation can be understood in particular to be an encapsulation which has been carried out after the LED chip has been fitted.

For setting a color of the light emitted by the encapsulated LED chip, it may be advantageous for the encapsulation, in particular the potting compound, to have at least one wavelength-converting phosphor.

It is a special development, in particular in connection with a direct contact with the heat sink element, that the LED chip has an electrically insulating substrate. Suitable semiconductor layers may be applied to this substrate, e.g. by means of an epitaxy process, which produce an emitter surface, e.g. at a pn junction. In particular, the substrate may be a sapphire substrate which is electrically insulating and has a high thermal conductivity of 40 W / (m · K) at room temperature compared with other insulating materials.

It is a particularly preferred combination that at least one LED chip with a sapphire substrate rests directly on a heat sink element made of aluminum, since this results in a particularly good heat dissipation with a simultaneously high luminance and an inexpensive production.

It is further an embodiment that the heat sink element has at least one conductor for electrically contacting the at least one semiconductor light source and wherein between the at least one conductor track and the heat sink element, an electrically insulating insulating layer is present. This allows a secure wiring on electrically conductive heat sink elements. In an electrically non-conductive heat sink element can be dispensed with such an insulating layer.

The insulating layer is preferably applied by means of a printing method, in particular by means of a screen printing or stencil printing. Alternatively, the insulating layer may be applied via selective deposition methods or active patterning techniques, such as by coating, photopatterning and / or etching, etc.

If the at least one semiconductor light source also rests on an insulating layer, the insulating layer may be a single, continuous insulating layer.

If the at least one semiconductor light source rests directly on the heat sink element, the insulating layer preferably has a respective cutout at a placement location of the semiconductor light source.

It is also an embodiment that a plurality of semiconductor light sources are arranged in series on at least one end face of at least one plate-shaped heat sink element, in particular equidistantly from one another, wherein a conductor track is arranged between two adjacent semiconductor light sources. The series arrangement enables a high luminance as well as a simple wiring and assembly of the semiconductor light sources. The equidistant spacing allows a uniform distribution of the light intensity and a uniform heat dissipation over the length of the heat sink element.

A trace may be electrically contacted with an adjacent semiconductor light source in various ways, e.g. by a pressure contact, a soldering, wire bonding, etc.

The conductor may in particular comprise silver, e.g. be made of a silver paste. The conductor track may in particular have been produced from a sinterable silver.

The conductor can be printed in particular.

It is also an embodiment that the semiconductor lighting device comprises a plurality of semiconductor light sources, which are electrically connected in series at least with respect to a heat sink element. Such an electrical connection is particularly easy to implement.

It is yet another embodiment that the end face of the at least one plate-shaped heat sink element has a width of not more than 5 mm, in particular of not more than 2 mm, in particular of about 1 mm. As a result, a particularly high luminance is made possible, in particular when using LED chips as the semiconductor light sources.

In particular, a width of 1 mm has proved to be advantageous for LED chips, since this width still allows safe placement and effective heat dissipation from the LED chips, and indeed by a convective cooling of the at least one plate-shaped heat sink element. A use of several, correspondingly thinner plate-shaped heat sink elements as a carrier, in particular for only 0.25 mm wide LED chip would be disadvantageous, if only because of the difficult production and handling of the thinner heat sink elements.

It is also an embodiment that the plate-shaped heat sink element is cuboid and a length between about 400 mm and 800 mm, in particular of about 600 mm, and a height between about 15 mm and 25 mm, in particular of about 20 mm , having. These dimensions have proven to be compact yet effective in convective dissipation of heat from the at least one semiconductor light source, particularly the at least one LED chip, particularly at a power density of 3000 lm / m, as are advantageous for retrofit fluorescent tubes. For example, a temperature at a pn junction of the semiconductor light source (s) can remain below 100 ° C. This is especially true in combination with the above-mentioned width, in particular of about 1 mm. Particularly preferred is a cuboid heat sink element made of aluminum with a length of about 600 mm, a height of about 20 and a width of about 1 mm.

It is also an embodiment that the semiconductor lighting device comprises a plurality of plate-shaped heat sink elements assembled into a stack. Such a semiconductor lighting device allows a particularly high, by means of a number of plate-shaped heat sink elements scalable light intensity.

In other words, the semiconductor lighting device has a plurality of plate-shaped heat sink elements assembled to form a stack, of which at least one heat sink element, in particular all heat sink elements, are designed as described above.

It is a preferred embodiment for a high light intensity that the plate-shaped heat sink elements form a completely compact body. Such a completely compact body can in particular be understood as meaning a body composed of heat sink elements which does not have a defined gap between adjacent heat sink elements. Such a completely compact body can also be understood as meaning a body composed of heat sink elements, in which adjacent heat sink elements over the entire surface. Thus, a basically arbitrarily high number of heat sink elements can be assembled into a stack. For this purpose, no preparation or post-processing, such as bending, the heat sink elements necessary. In cuboid heat sink elements in particular a cuboid stack can result. Nevertheless, there is sufficient heat dissipation in a convective cooling of the stack, eg by blowing cooling air by means of a fan.

It is a further development that a common electrical insulating layer is applied to at least one surface of the stack, which results from adjacent end faces of the heat sink elements, and which is provided for equipping with semiconductor light sources ("placement surface"). So a simple and large-scale electrical insulation is possible. In the case of semiconductor light sources to be applied directly to the heat sink elements, corresponding recesses may be present in the electrical insulation layer at the placement locations.

It is still a development of the stack that a wiring, in particular at least one conductor track and / or at least one bonding wire or the like, is present between end faces of at least two heat sink elements. This facilitates an electrical connection to an external power supply. For example, rows of semiconductor light sources of adjacent heat sink elements may be connected together in series or in parallel.

The heat sink elements can be welded, glued, screwed, clamped u.v.m. become.

It is yet another embodiment that the semiconductor light-emitting device is a retrofit lamp or a part thereof. In particular, in a replacement of a conventional lamp by an externally similar shaped retrofit lamp, the possibility of compact design at high light intensity (preferably 3000 lm / m) is advantageously used. The retrofit lamp may in particular be a retrofit fluorescent tube.

The object is also achieved by a method for producing a semiconductor light-emitting device comprising a plurality of plate-shaped heat sink elements assembled into a stack, wherein (a) a plurality of electrically conductive, plate-shaped heat sink elements are assembled into a stack; (B) on at least one placement surface of the stack, which results from adjacent end faces of the heat sink elements, an electrical insulating layer is applied; (C) at least one conductor track is applied to the electrical insulating layer; (d) the at least one placement surface is equipped with at least one semiconductor light source; and (e) the at least one semiconductor light source is electrically contacted with the at least one conductive trace.

This method enables a simple and inexpensive production of the semiconductor light-emitting device. The method can be configured in particular analogously to the semiconductor lighting device.

For example, the method may comprise the following step: (e) encapsulating, in particular casting, the at least one semiconductor light source, in particular encapsulation material exposed to a phosphor. Thus, protection of the at least one semiconductor light source is achieved.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an embodiment which will be described in detail in conjunction with the drawings. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows an oblique view of a plate-shaped heat sink element of a semiconductor light-emitting device according to the invention;

2 shows an oblique view of a composite of the plate-shaped heat sink elements stack of semiconductor lighting device according to the invention 1 ; and

3 shows an oblique view of a section of the semiconductor light-emitting device according to the invention.

1 shows an oblique view of a plate-shaped heat sink element 1 a semiconductor light-emitting device F according to the invention. The plate-shaped heat sink element 1 is in the form of a cuboidal plate ("blade") made of aluminum with a purity of at least 90%, in particular at least 95%.

The heat sink element 1 has a length of L = 600 mm, a height of H = 20 mm and a width of B = 1 mm. This is a long front page 2 determined by the length L and the width B, and a short end face 3 by the height H and the width B. In the long side determined by the length L and the height H. 4 are three circular recesses 5 introduced, which are provided for screwing in particular in the case of a parallel production.

2 shows an oblique view of an n (n> 1) plate-shaped heat sink elements 1 composite pile 6 the semiconductor light-emitting device F. The heat sink elements 1 are like that with their broadsides 4 congruent and thus set over the entire area that a cuboid stack 6 with the same length L and height H but a width of n · B.

Such a compact stack 6 has the advantage that it can be attached by adding additional heat sink elements 1 can be extended arbitrarily in width without further ado. A fixation of the heat sink elements 1 can be done for example by means of fasteners such as screws, etc., which through the recesses 5 be guided.

Now, on at least one Bestückoberfläche 7 of the pile 6 , which consist of adjacent end faces 2 and or 3 the heat sink elements 1 results in a common electrical insulating insulating layer 8th (please refer 3 ), for example by means of screen printing or stencil printing. This can be placement for directly on the front pages 2 and or 3 the heat sink elements 1 applied semiconductor light sources in the form of LED chips 9 (please refer 3 ) be omitted.

Following can on the insulating layer 8th conductor tracks 10 (please refer 3 ) are applied from a silver-containing material, which in particular Bestückplätze a heat sink element 1 connect with each other. This can be achieved for example by a printing process.

In a further step, the placement surface 7 that's here from the front pages 2 is formed at the slots with the LED chips 9 be fitted. This will be the LED chips 9 equidistant in series to exactly one associated heat sink element 1 placed. The LED chips 9 a heat sink element 1 are thus electrically connected in series.

Following are the LED chips 9 with adjacent tracks 10 electrically contacted, for example by wire bonding ("wire bonding").

In a next step, the previously naked LED chips 9 be cast by potting with an applied with phosphor potting compound. This protects the LED chips 9 and their electrical contacts.

In addition, conductor tracks can 10 various heat sink elements 1 electrically connected to each other, for example by means of wire bonding, soldering, etc.

The semiconductor light-emitting device F may further be provided with a driver, housed, etc.

3 shows an oblique view of a section of the semiconductor light-emitting device F on one of the heat sink elements 1 ,

The LED chips 9 have already been shown shed here. The LED chips 9 lie directly on the associated heat sink element 1 on. The LED chips 9 are equipped with a sapphire substrate, so that a good dissipation of the through the LED chip 9 generated heat loss on the heat sink element 1 can achieve at a simultaneous electrical insulation.

The LED chips 9 are each other so on the respective heat sink element 1 arranged at a distance that results in a power density of 3000 lm / m. The resulting waste heat can by means of the stack 6 alone by means of a convective cooling dissipated. This makes it possible, for example, a temperature at a pn junction of the LED chips 9 keep below 100 ° C.

This semiconductor light-emitting device F is particularly suitable for use in a retrofit fluorescent tube.

While the invention has been further illustrated and described in detail by the illustrated embodiment, the invention is not so limited and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

Heat sink element

2

long frontal

3

short front

4

broadside

5

circular recess

6

stack

7

Bestückoberfläche

8th

insulating

9

LED chip

10

conductor path

F

Semiconductor light emitting device

H

height

B

width

L

length

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7878686 B2 [0002]

Claims (14)

Semiconductor lighting device (F), comprising at least one semiconductor light source ( 9 ) on at least one end face ( 2 . 3 ) of a thermally highly conductive, plate-shaped heat sink element ( 1 ), wherein the at least one semiconductor light source ( 9 ) of exactly one heat sink element ( 1 ) will be carried. Semiconductor lighting device (F) according to claim 1, wherein the heat sink element ( 1 ) is electrically conductive, the at least one semiconductor light source ( 9 ) directly on the heat sink element ( 1 ) rests and the at least one semiconductor light source ( 9 ) relative to the heat sink element ( 1 ) Is designed electrically isolated. Semiconductor lighting device (F) according to claim 1, wherein the heat sink element ( 1 ) is electrically conductive and between the at least one semiconductor light source ( 9 ) and the heat sink element ( 1 ) an electrically insulating insulating layer is present. Semiconductor lighting device (F) according to one of the preceding claims, wherein the at least one plate-shaped heat sink element ( 1 ) consists of aluminum. Semiconductor lighting device (F) according to one of the preceding claims, wherein the at least one semiconductor light source ( 9 ) is present in the form of at least one LED chip. Semiconductor lighting device (F) according to one of the preceding claims, wherein the heat sink element ( 1 ) at least one conductor track ( 10 ) for electrically contacting the at least one semiconductor light source ( 9 ) and wherein between the at least one conductor track ( 10 ) and the heat sink element ( 1 ) an electrically insulating insulating layer ( 8th ) is available. Semiconductor lighting device (F) according to one of the preceding claims, wherein on at least one end face ( 2 . 3 ) at least one plate-shaped heat sink element ( 1 ) a plurality of semiconductor light sources ( 9 ) are arranged in series, in particular equidistant from each other, wherein between two adjacent semiconductor light sources ( 9 ) a conductor track ( 10 ) is arranged. Semiconductor lighting device (F) according to one of the preceding claims, wherein the semiconductor lighting device (F) a plurality of semiconductor light sources ( 9 ), which are electrically connected in series. Semiconductor lighting device (F) according to one of the preceding claims, wherein the end face ( 2 . 3 ) of the at least one plate-shaped heat sink element ( 1 ) has a width (B) of not more than 5 mm, in particular of not more than 2 mm, in particular of about 1 mm. Semiconductor lighting device (F) according to one of the preceding claims, wherein the plate-shaped heat sink element ( 1 ) is cuboidal and has a length (L) between about 400 mm and 800 mm, in particular of about 600 mm, and a height (H) between about 15 mm and 25 mm, in particular of about 20 mm. Semiconductor lighting device (F) according to one of the preceding claims, comprising several to a stack ( 6 ) composite plate-shaped heat sink elements ( 1 ). Semiconductor lighting device (F) according to one of the preceding claims, wherein the semiconductor lighting device (F) is a retrofit lamp or a part thereof. A method for producing a semiconductor light-emitting device (F) according to claim 11, wherein - a plurality of electrically conductive, plate-shaped heat sink elements ( 1 ) to a stack ( 6 ); On at least one placement surface ( 7 ) of the stack ( 6 ), which consist of adjacent end faces ( 2 . 3 ) of the heat sink elements ( 1 ), an electrical insulating layer ( 8th ) is applied; - on the electrical insulating layer ( 8th ) at least one conductor track ( 10 ) is applied; The at least one placement surface ( 7 ) with at least one semiconductor light source ( 9 ) is fitted; and - the at least one semiconductor light source ( 9 ) with the at least one conductor track ( 10 ) is contacted electrically. The method of claim 13, wherein the method comprises the following step - encapsulating, in particular potting, the at least one semiconductor light source ( 9 ), in particular with a phosphor acted upon encapsulation material having.

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