DE102012101560B4 - light emitting diode device - Google Patents

Abstract

Light-emitting diode device (1) comprising a carrier (2) having a top side and a bottom side, a light-emitting diode chip (3) and at least one electrical component (41), - wherein the carrier (2) has a first cavity (51) arranged on top is, and at least one of them optically separate second cavity (52) which is arranged on the first cavity (51) opposite underside of the carrier (2), and - wherein the LED chip (3) in the first cavity (51) and the at least one electrical component (41) is at least partially sunk in the at least one second cavity (52), and at least one further electrical component (42) is arranged completely sunk in the at least one second cavity (52).

Description

The invention relates to a light-emitting diode device which has a light-emitting diode chip and at least one electrical component.

There are light-emitting diodes ("LEDs") are known in which an LED chip and a protective device are arranged on a flat support. By the protective device can be shaded light emitted by the LED chip light.

The publication US 2010/0 213 496 A1 shows an LED package having a carrier, a housing, an LED chip and a plurality of ESD protection elements. Increases are intended to prevent light emitted by the LED chip from being absorbed by the ESD protective elements.

In the publication US 2009/0 057 687 A1 there is described a light emitting diode device comprising a substrate having a plurality of recesses and a plurality of LEDs each disposed in one of the recesses.

The publication US 2009/0 278 162 A1 shows an LTCC carrier which is mounted on a main carrier and has a cavity in which a light-emitting diode chip is arranged. Thermal vias dissipate heat.

The publication US 2007/0 018 191 A1 shows a device with a cavity on top and bottom.

It is an object of at least some embodiments to provide an alternative light emitting diode device.

This object is achieved by an article according to the independent claim. Advantageous embodiments and further developments of the subject matter will become apparent from the dependent claims, the following description and the drawings, but the invention is defined in the most general form by the claim 1.

A light-emitting diode device according to at least one embodiment has a carrier. The carrier may comprise a base body, wherein the base body preferably has a good thermal conductivity.

For example, the carrier may have an electrically insulating base body. The electrically insulating base body has, for example, a ceramic material or consists of a ceramic material. Preferably, the base body comprises at least one of the materials of aluminum oxide or aluminum nitride or a ceramic of the type LTCC ("low temperature cofired ceramics") or consists of one of these materials. Furthermore, it is possible that the base body comprises an organic material. For example, the main body comprises a printed circuit board which comprises an organic material.

According to a further embodiment, the carrier has a metallic base body or consists of a metallic base body. For example, the metallic base body comprises aluminum or copper or consists of one of these materials.

The light-emitting diode device furthermore has a light-emitting diode chip. The light-emitting diode chip preferably has at least one of the following materials:
Gallium phosphide (GaP), gallium nitride (GaN), gallium arsenic phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), aluminum gallium phosphide (AlGaP), aluminum gallium arsenide (AlGaAs), indium gallium nitride (InGaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), aluminum gallium indium nitride (AlGaInN), Zinc selenide (ZnSe).

Furthermore, the light-emitting diode device has at least one electrical component. Preferably, the at least one electrical component is a discrete electrical component that has no optoelectronic properties. This may mean in particular that the at least one electrical component is neither a light-emitting nor a light-receiving electrical component. The at least one electrical component may, for example, be connected to the LED chip in order, as described below, to protect the LED chip from damaging electrical influences such as electrostatic discharges or overcurrent.

According to the invention, the carrier has a first cavity and at least one second cavity. The cavities are formed, for example, by depressions on surfaces of the carrier and in particular of the base body.

According to the invention, the light-emitting diode chip is arranged at least partially recessed in the first cavity. For example, the light-emitting diode chip can be arranged in the first cavity such that regions of the light-emitting diode chip can project beyond the cavity. In this case, it can be particularly advantageous if an active region of the light-emitting diode chip, in which light is generated during operation, is arranged below an upper edge of the first cavity. According to a preferred embodiment, the light-emitting diode chip is in the first cavity completely sunk. That a component in a cavity is "completely submerged" means that the cavity has a depth that is greater than or equal to a height of the component disposed in the cavity such that no portion of the component protrudes beyond the cavity.

According to a further embodiment, the first cavity has a bottom surface and side surfaces. The side surfaces preferably run obliquely to the bottom surface. For example, the side surfaces with the bottom surface each include an angle between 120 ° and 150 °. According to a preferred embodiment, the side surfaces with the bottom surface in each case an angle between 130 ° and 140 °.

Particularly preferably, the side surfaces with the bottom surface each enclose an angle of 135 °.

According to a further embodiment, the first cavity has a reflective layer. For example, the side surfaces and / or the bottom surface of the first cavity may be coated with the reflective layer.

By means of the obliquely to the bottom surface extending side surfaces of the first cavity and arranged on the side surfaces and / or the bottom surface reflective layer, a particularly good yield of light emitted from the LED chip can be achieved because the portion of the light from the LED chip in operation in the direction the side walls and / or the bottom surface of the first cavity is radiated out of the cavity can be reflected.

According to the invention, the at least one electrical component is at least partially recessed in the at least one second cavity. For example, areas of the at least one electrical component may protrude beyond the at least one second cavity. Particularly preferably, the at least one electrical component in the at least one second cavity is arranged completely submerged. Preferably, no regions of the at least one electrical component protrude out of the cavity. As a result, it can advantageously be achieved that shading of the light emitted by the light-emitting diode chip during operation of the light-emitting diode device is prevented by the at least one electrical component or by parts of the at least one electrical component.

According to the invention, the first cavity is optically separated from the second cavity on the carrier. The term "optically separated" may in this case mean, in particular, that light emitted by the light-emitting diode chip can not impinge directly on the cavity, that is, the cavity can not directly illuminate without, for example, being previously reflected.

According to the invention, the light-emitting diode device has a carrier, a light-emitting diode chip and at least one electrical component, wherein the carrier has a first cavity and at least one optically separate second cavity, and wherein the light-emitting diode chip in the first cavity and the at least one electrical component in the at least one second cavity are arranged at least partially and preferably completely submerged.

In the case of the light-emitting diode device described here, it can be achieved that the light-emitting diode device has particularly small dimensions, in particular a particularly low structural height, which plays an increasingly important role in the design of light-emitting diode devices. Especially in mobile applications, for example, for an integrated LED camera flash in smart phones or digital cameras, light-emitting diode chip and other discrete components should take up as little space as possible.

According to a further embodiment, the at least one electrical component is an ESD protection component, "ESD" here and hereinafter standing for "electrostatic discharge". The ESD protection component is preferably used to protect the LED chip from overvoltages, especially against electrostatic discharges. In general, light-emitting diode chips are very sensitive to electrostatic discharges, especially those with a voltage greater than 100 volts, and therefore must be protected by protective devices. By way of example, the ESD protection component may be designed in the form of a multilayer varistor, also referred to as a multi-layer varistor (MLV). Furthermore, it is possible for the ESD protection component to be in the form of a suppressor diode, in particular a transient voltage suppressor diode (TVS diode).

According to a further embodiment, the ESD protection component is a multi-layer varistor which has a varistor ceramic. Preferably, the varistor ceramic has or consists of a system of ZnO-Pr, ZnO-Bi-Sb, SrTiO ₃ or SiC. According to a further embodiment, the ESD protection component comprises a ceramic comprising or consisting of a composite of a varistor material and a metal.

According to a further embodiment, the at least one electrical component has at least two contact surfaces. Preferably, the contact surfaces are solderable. For example, show the contact surfaces are or consist of an alloy or a layer sequence with one of the following material combinations: Cu / Ni / Au, Cr / Ni / Au, Cr / Cu / Ni / Au.

According to a further embodiment, the at least one electrical component is a thermistor component. The thermistor device can be designed, for example, as a so-called NTC thermistor device, where "NTC" stands for "negative temperature coefficient". An NTC thermistor device is characterized in that current is better conducted at high temperatures than at low temperatures. Therefore, the NTC thermistor device can also be referred to as a thermistor.

Preferably, the NTC thermistor device functions as a thermal sensor. The thermal sensor is preferably connected to the LED chip. For example, the thermal sensor can contribute to the regulation of a control current of the LED chip, so that it can be operated gently. As a result, advantageously, the life of the LED chip can be increased.

Furthermore, it is possible for the thermistor component to be designed as a so-called PTC thermistor component, where "PTC" stands for "positive temperature coefficient". The PTC thermistor component is preferably connected to the LED chip. In a PTC thermistor device, current is better conducted at low temperatures than at high temperatures, which is why the PTC thermistor device is also referred to as a PTC thermistor. Preferably, the PTC thermistor device functions as an overcurrent protection element and protects the LED chip from excessive operating currents, whereby the life of the LED chip can be increased.

The at least one second cavity can be arranged according to an alternative not claimed in the same surface of the carrier as the first cavity, whereby, for example, the LED chip and the at least one electrical component in the at least one second cavity can be interconnected via short paths.

However, the at least one second cavity is arranged according to claim 1 on an opposite side of the first cavity of the carrier. For example, a surface of the base body, which faces the surface of the carrier provided with the first cavity, which may form the upper side of the carrier, has a depression which forms the at least one second cavity. This can advantageously be achieved that the light-emitting diode device can be made very compact. Furthermore, it can be prevented by such an arrangement that an electrical component arranged in the second cavity partially shields a light emission of the light-emitting diode chip. At least one further electrical component is arranged completely sunk in the at least one second cavity. In other words, the at least one second cavity can be designed so that at least two electrical components can be arranged therein. As a result, a particularly compact design of a light-emitting diode device having a light-emitting diode chip and at least two electrical components can be achieved.

According to a further embodiment, the carrier has a further second cavity, in which a further electrical component is arranged completely submerged. The further second cavity can be arranged, for example, on the same side of the carrier on which the first cavity is arranged. Alternatively, the further second cavity may be arranged, for example, on the side of the carrier opposite the first cavity.

According to a further preferred embodiment, the light-emitting diode device has an ESD protection component, an NTC thermistor component and a PTC thermistor component, which are arranged completely submerged in a respective second cavity or even in two or three threes in a same second cavity. As a result, in such a light-emitting diode device, an integration of protective components against electrostatic discharges, for example in the form of an MLV or a TVS diode, protection components against overcurrents, for example in the form of a PTC thermistor device, and of temperature sensors, for example in the form of an NTC thermistor device together can be achieved with a particularly low height of the light emitting diode device.

According to a further embodiment, the carrier has an insulating base body, which is provided and arranged as a heat-dissipating element for the LED chip and / or the at least one electrical component.

According to a further embodiment, the insulating base body has vias. Via stands for "vertical interconnect access" and refers to a via. Preferably, at least one via is designed as a thermal via, ie as a thermally conductive via. Furthermore, several or all vias may be formed as thermal vias. The at least one thermal via can advantageously improve the dissipation of heat away from the light-emitting diode chip. Preferably, the at least one thermal via has a material with a good thermal conductivity. By way of example, the at least one via can extend from the bottom surface of the first cavity to a surface of the carrier which faces away from the first cavity, in particular opposite one another. For example, the at least one via comprises or consists of copper, silver or silver-palladium. Furthermore, it may also be possible for at least one via to be provided, which serves as electrical supply line between the light-emitting diode chip and an electrical connection surface in the form of a metallization arranged on a surface of the carrier facing away from the first cavity.

According to a further embodiment, the first cavity is at least partially covered by a protective coating. Preferably, the LED chip is at least partially enclosed by the protective coating. The protective coating can serve as a lens of the light-emitting diode device. Furthermore, it is possible that the at least one second cavity and / or the at least one electrical component are at least partially covered by the protective coating. The protective coating preferably comprises silicone or is made of silicone.

According to a further embodiment, the carrier has a metallization on a side facing away from the first cavity. The metallization may extend over the entire, the first cavity facing away from the carrier. Alternatively, the metallization may extend over a portion of the first cavity side facing away from the carrier. The metallization preferably serves for the electrical connection of the light-emitting diode device, for example to a substrate or to a printed circuit board.

According to a further embodiment, the carrier has a main body which comprises a ceramic partial body and a metallic partial body. Preferably, the first and the at least one second cavity are arranged in the ceramic part body. The ceramic part body and the metallic part body may be separated from each other by means of an insulating layer. For example, the metallic part body may be coated with the insulating layer. The insulation layer is preferably an electrically insulating layer. For example, the insulating layer may comprise a ceramic material or consist of a ceramic material. The insulating layer may comprise, for example, aluminum oxide, aluminum nitride or an LTCC ceramic or consist of one of these materials.

The light emitting diode device described here is characterized in particular by a low height and a good thermal management. Furthermore, it can be achieved in a light-emitting diode device described here that the emission of the light-emitting diode chip is not adversely affected by electrical components, such as, for example, ESD protection components or thermal sensors.

Further advantages and advantageous embodiments of the light-emitting diode device will become apparent from the examples described below in conjunction with FIGS. 1 to 8, hereinafter referred to as embodiments, but the invention is defined in the most general form by claim 1.

Show it:

1 a schematic sectional view of a light-emitting diode device according to an embodiment and

2 to 8th schematic sectional views of light emitting diode devices according to further embodiments.

In the exemplary embodiments and figures, identical or identically acting components may each be provided with the same reference numerals. The illustrated elements and their proportions with each other are basically not to be considered as true to scale. Rather, individual elements such as layers, components and areas for better representability and / or for better understanding can be shown exaggerated thick or large dimensions.

1 shows a schematic sectional view of a light-emitting diode device 1 according to a first embodiment.

The light-emitting diode device 1 includes a carrier 2 , which is an insulating body 21 made of alumina. Alternatively, the main body 21 For example, also have aluminum nitride. Aluminum oxide and aluminum nitride are characterized in particular by a high thermal conductivity and a high dielectric strength. The carrier 2 has a first cavity 51 and a second cavity optically separated from the first cavity 52 in a surface, in particular in the embodiment shown in the same surface, of the carrier 2 and in particular of the basic body 21 on.

The light-emitting diode device 1 furthermore comprises a light-emitting diode chip 3 and at least one electrical component 41 , which is executed in the embodiment shown as an ESD protection device in the form of a multi-layer varistor. Alternatively, the electrical component 41 also as TVS Diode, be designed as NTC thermistor device or PTC thermistor device. The LED chip 3 is in the first cavity 51 at least partially recessed, while the electrical component 41 in the second cavity 52 at least partially sunk. Advantageously, the LED chip 3 or the electrical component 41 , or, as in the embodiment according to 1 shown, both the LED chip 3 and the electrical component 41 completely submerged in the first or second cavity 51 . 52 arranged so that the electrical component 41 optically separated from the LED chip 3 is. By sinking the electrical component 41 in the second cavity 52 can thus be advantageously prevented that of the LED chip 3 radiated light directly onto the electrical component 41 which leads to shading by the electrical component 41 would lead.

The first cavity 51 has a bottom surface 71 as well as two to the bottom surface 71 at an angle greater than or equal to 120 ° and less than or equal to 150 ° inclined side surfaces 72 on. The floor area 71 and the side surfaces 72 are provided with a reflective layer (not shown). By means of the reflective layer, a luminous efficiency of a light emitting diode chip 3 radiated light can be improved by the LED chip 3 radiated light incident on the surfaces coated with the reflective layer incident light to a large extent and is not absorbed.

The LED chip 3 has contact surfaces, the contacting and / or the mounting of the LED chip 3 serve and of which purely by way of example a contact surface 10 is shown, with the LED chip 3 on the floor surface 71 the first cavity is attached. Preferably, the LED chip is on the bottom surface 71 soldered. The contact surface 10 has a gold-tin alloy. Alternatively, the contact surface 10 Copper, nickel or gold or an alloy or layer sequence of at least two of these materials.

Due to the high thermal conductivity of the main body 21 is from the LED chip 3 Heat generated during operation is good from the LED chip 3 diverted. As a result, the light emitting diode device 1 a good thermal management. Due to a reduced heat load, the life of the LED chip 3 be significantly extended. For example, with a 20 ° C reduced operating temperature of the LED chip 3 the life of the LED chip 3 by the factor 2 increase.

The electrical component 41 has two contact surfaces 10 on top of it, on a bottom surface of the second cavity 52 is attached. Alternatively, the electrical component 41 also more contact surfaces 10 exhibit. The contact surfaces 10 serve the electrical contact and the assembly of the electrical component 41 , The contact surfaces 10 have an alloy or layer sequence of Cu / Ni / Au. Alternatively, the contact surfaces 10 an alloy or layer sequence of Cr / Ni / Au or of Cr / Cu / Ni / Au.

On the first cavity 51 opposite side of the carrier 2 is a metallization 12 applied. The metallization 12 serves for electrical connection of the light-emitting diode device 1 , The carrier 2 and in particular the basic body 21 also has plated-through holes and / or printed conductors for interconnecting the elements shown, which are not shown for the sake of clarity.

Furthermore, the LED chip 3 and the electrical component 41 from a protective coating 11 enclosed. The protective coating 11 has silicone and acts as a lens. Furthermore, the protective coating can 11 serve as a wavelength conversion layer. As an alternative to the exemplary embodiment shown, the light-emitting diode device can also not have a protective coating 11 or only partially, for example over the LED chip 3 , be provided with a protective coating.

The further figures show exemplary embodiments, the modifications and variants of in 1 shown embodiment and are therefore explained above all in view of the differences thereto.

In 2 is a schematic sectional view of a light-emitting diode device according to another embodiment shown. Unlike the in 1 shown embodiment, two electrical components in the second cavity 41 . 42 completely sunk. It is one of the two electrical components 41 . 42 designed as ESD protection device and the other as a thermistor device. By such an arrangement, a particularly compact design of a light emitting diode device 1 , which a LED chip 3 and two electrical components 41 . 42 has to be achieved.

3 shows a light emitting diode device 1 according to a further embodiment. Unlike the in 1 embodiment shown, the insulating body 21 vias 8th on, which are designed as thermal vias. The vias 8th are from the contact area 10 of the LED chip 3 isolated electrically conductive and serve the heat dissipation of the LED chip 3 operational generated heat. The vias 8th have copper in the embodiment shown for this purpose. Alternatively, the vias 8th also have other materials with a high thermal conductivity, such as silver or silver-palladium. The vias 8th extend approximately perpendicular to a surface of the body 21 , Furthermore, one or more vias, preferably at least two vias, can be embodied as electrical vias which are electrically conductive with contact surfaces 10 of the LED chip 3 are connected and the electrical contact of the LED chip 3 serve.

In 4 is a light-emitting diode device 1 shown according to another embodiment. Unlike the in 3 embodiment shown, the carrier 2 on the metallization 12 opposite side another second cavity 53 on, in which another electrical component 42 completely sunk. The light-emitting diode device 1 thus comprises two electrical components 41 . 42 that exist in different cavities 52 . 53 are arranged. Preferably, one of the two electrical components 41 . 42 designed as ESD protection device and the other as a thermistor device.

5 shows a schematic sectional view of a light-emitting diode device 1 according to a further embodiment. Unlike the in 4 In the embodiment shown, the further second cavity is on one of the first cavities 51 opposite side of the carrier 2 arranged. This advantageously allows a particularly compact light-emitting diode device 1 be achieved.

In 6 is a schematic sectional view of a light-emitting diode device according to another embodiment shown. Unlike those in the 4 and 5 shown embodiments, the carrier 2 three second cavities 52 . 53 . 54 on, with two of the second cavities 52 . 54 on the same side of the carrier 2 are arranged, on which also the first cavity 51 is arranged, and wherein one of the second cavities 53 on one of the first cavity 51 opposite side of the carrier 2 is arranged. In the second cavities 52 . 53 . 54 is in each case an electrical component 41 . 42 . 43 completely sunk.

7 shows a schematic sectional view of a light-emitting diode device 1 according to a further embodiment. The carrier 2 has a basic body 21 on, a ceramic part body 22 and a metallic part body 23 includes. The first and two second cavities 51 . 52 . 53 are in the ceramic part body 22 arranged. The ceramic part body 22 and the metallic part body 23 are by means of a ceramic insulation layer 9 separated from alumina. Alternatively, the insulating layer may also comprise aluminum nitride or an LTCC ceramic. The metallic part body 23 has aluminum and acts as in the light emitting diode device 1 integrated heat sink, which in operation of the LED chip 3 and / or of the electrical components 41 . 42 dissipates generated heat. Alternatively, the metallic part body 23 also comprise copper or consist of copper.

In 8th is a light-emitting diode device 1 shown according to another embodiment. The LED chip 3 is at least partially recessed in the first cavity compared to the previous embodiments 51 arranged. In particular, the LED chip 3 so far in the first cavity 51 be sunk that an active area of the LED chip 3 in which light is generated in operation, below the upper edge of the first cavity 51 is arranged. Alternatively, the LED chip 3 as in the previous embodiments also completely submerged in the first cavity 51 be arranged. The carrier 2 the light emitting diode device 1 has a metallic base body 21 made of aluminum or consists of it. Alternatively, the metallic base body 21 also comprise copper or consist of copper.

Furthermore, between the LED chip 3 and the metallic base body 21 as well as between the electrical components 41 . 42 and the metallic base body 21 each a ceramic insulation layer 9 arranged so that the components can be prevented 3 . 41 . 42 be shorted. The ceramic insulation layer 9 has alumina. Alternatively, the insulating layer may also comprise aluminum nitride or an LTCC ceramic.

In a light emitting diode device according to the embodiment according to 8th can be particularly well ensured that by means of the metallic body 21 a lot of heat from the LED chip 3 is removed, thereby avoiding a high operating temperature and thus the life of the LED chip 3 can be significantly increased.

The features described in the exemplary embodiments shown can also be combined with each other according to further embodiments, even if such combinations are not explicitly shown in the figures. Furthermore, the light-emitting diode devices shown can have further or alternative features according to the embodiments described above in the general part.

LIST OF REFERENCE NUMBERS

1

light emitting diode device

2

carrier

21

body

22

ceramic part body

23

metallic part body

3

LED chip

41

electrical component

42, 43

another electrical component

51

first cavity

52

second cavity

53

another second cavity

71

floor area

72

side surface

8th

Via

9

insulation layer

10

contact area

11

protective coating

12

metallization

Claims (13)

Light emitting diode device ( 1 ) comprising a carrier ( 2 ) having a top side and a bottom side, a light-emitting diode chip ( 3 ) and at least one electrical component ( 41 ), - the carrier ( 2 ) a first cavity ( 51 ), which is arranged on the upper side, and at least one of them optically separate second cavity ( 52 ), which on the first cavity ( 51 ) opposite underside of the carrier ( 2 ), and - wherein the light-emitting diode chip ( 3 ) in the first cavity ( 51 ) and the at least one electrical component ( 41 ) in the at least one second cavity ( 52 ) are at least partially sunk, - and wherein at least one further electrical component ( 42 ) completely sunk in the at least one second cavity ( 52 ) is arranged. Light-emitting diode device according to Claim 1, in which the light-emitting diode chip ( 3 ) in the first cavity ( 51 ) and the at least one electrical component ( 41 ) in the at least one second cavity ( 52 ) are arranged completely submerged. Light-emitting diode device according to one of the preceding claims, in which the carrier ( 2 ) another second cavity ( 53 ), in which a further electrical component ( 42 ) is arranged completely submerged. Light-emitting diode device according to one of the preceding claims, in which the at least one electrical component ( 41 ) is an ESD protection device, which is designed in the form of a multi-layer varistor. Light-emitting diode device according to one of the preceding claims, in which the at least one electrical component ( 41 ) is an ESD protection device, which is designed in the form of a TVS diode. Light-emitting diode device according to one of the preceding claims, in which the at least one electrical component ( 41 ) is a thermistor device. Light-emitting diode device according to one of the preceding claims, in which an ESD protection component, an NTC thermistor component and a PTC thermistor component in one or more second cavities ( 52 . 53 ) are arranged completely submerged. Light-emitting diode device according to one of the preceding claims, in which the first cavity ( 51 ) a floor surface ( 71 ) as well as side surfaces ( 72 ), wherein the side surfaces ( 72 ) obliquely to the bottom surface ( 71 ). Light-emitting diode device according to one of the preceding claims, in which the carrier ( 2 ) an insulating base body ( 21 ) comprising a ceramic or an organic material. Light-emitting diode device according to Claim 9, in which the insulating base body ( 21 ) AlO _x , AlN or a LTCC type of ceramics, LTCC being Low Temperature Cofired Ceramics. Light-emitting diode device according to one of Claims 9 or 10, in which the insulating base body ( 21 ) Vias ( 8th ), wherein at least one via is designed as a thermal via. Light-emitting diode device according to one of Claims 1 to 8, in which the carrier ( 2 ) a metallic base body ( 21 ) having. Light-emitting diode device according to one of Claims 1 to 8, in which the carrier ( 2 ) a basic body ( 21 ) comprising a ceramic part body ( 22 ) and a metallic part body ( 23 ), wherein the first and the at least one second cavity ( 51 . 52 ) in the ceramic part body ( 22 ) are arranged, and wherein the ceramic part body ( 22 ) and the metallic part body ( 23 ) by means of an insulating layer ( 9 ) are separated from each other.

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