LED MODULE

Abstract

The invention relates to an LED module with a circuit which comprises an LED (106) and a resonant circuit (106, 108, 110) for coupling in energy for operation of the LED, wherein the circuit is formed without connections and is fully encapsulated in the LED module.

Claims

1. An LED module with a circuit, which comprises an LED and a resonant circuit for coupling in energy for operating the LED, wherein the circuit is formed without connections and is fully encapsulated in the LED module.

2. The LED module according to claim 1 with a dielectric, wherein first and second electrodes for contacting the LED are arranged on mutually opposed sides of a dielectric, such that a capacitance for the resonant circuit is formed hereby.

3. The LED module according to claim 2 with a layered structure, wherein the first electrode for contacting the LED is arranged on a first layer and an antenna having a plurality of antenna windings about the first electrode is arranged on the first layer, wherein a first end of the antenna is electrically connected to the first electrode, with a second layer, which contains the dielectric and the LED, and with a third layer, on which a second electrode for contacting the LED is arranged, wherein the second electrode is contacted with a second end of the antenna by means of a via through the second layer and a capacitance is formed by the first and second electrodes with the dielectric arranged therebetween, such that the resonant circuit is formed hereby.

4. The LED module according to claim 2, with a layered structure, wherein a portion of the first electrode is arranged on one side of the dielectric and the second electrode is arranged on the opposite side of the dielectric, wherein the LED has first and second connections, which are arranged on the same side of the LED, wherein one of the connections of the LED is connected to the portion of the electrode by means of a via which runs through the dielectric, and wherein a conductive track of an antenna of the resonant circuit is arranged on the same side as the portion of the dielectric and is connected to the second electrode by means of a via which runs through the dielectric, wherein the second electrode is connected to the second connection of the LED.

5. The LED module according to claim 3, wherein the resonance frequency of the resonant circuit is given by the inductance of the antenna and the sum of the capacitance of the LED and the capacitance formed by the first and second electrodes with the dielectric disposed therebetween.

6. The LED module according to claim 3, wherein a coil opening is formed by the antenna windings, within which opening the first electrode is disposed, wherein a flat region of the second electrode extends over the coil opening, wherein the second electrode has a protrusion which connects the flat region and the via to one another, wherein the protrusion extends over the antenna windings.

7. The LED module according to claim 3, wherein a capacitance for the resonant circuit is formed by the parasitic capacitance of the antenna windings.

8. The LED module according to claim 7, wherein the antenna windings are arranged on mutually opposed sides of the dielectric, wherein the antenna windings are connected to one another by means of vias.

9. The LED module according to claim 3, wherein the width of a conductor of the antenna winding is between 5 and 15 μm and wherein distance between two adjacent antenna windings is between 5 μm and 15 μm and wherein the number of windings is between 20 and 60 windings.

10. The LED module according to claim 1, wherein an optically effective material is arranged in a light path of the light to be emitted by the LED, the optically effective material comprising a fluorescent or phosphorescent substance, dye for filtering the light, conversion phosphor, metal oxide particles, and/or retroreflective particles.

11. The LED module according to claim 1, wherein the resonance frequency of the resonant circuit is between 10 MHz and 16 MHz, in particular is 13.56 MHz.

12. The LED module according to claim 1, wherein the LED has a thickness of less than 100 μm and the LED module has an overall height of less than 7000 μm, wherein a lateral dimension of the LED module is less than 5 mm.

13. A paper having one or more LED modules according to claim 1 arranged in or on the paper.

14. A plastic or textile having one or more of the LED modules according to claim 1 arranged in or on the plastic or the textile.

15. A document of value or security document having a document body in or on which one or more LED modules according to claim 1 is/are arranged.

16. The document of value or security document according to claim 15 with a processor, a data memory and a communication interface, wherein the processor is configured to allow external access to the data memory via the communication interface only if a cryptographic protocol for authentication and/or authorisation check of an external reader has been carried out successfully, wherein the LED module can be controlled neither by the processor nor via the communication interface.

17. A movable good, item of clothing, container, in particular a beverage container, electronic unit, machine part, replacement part, pharmaceutical drug, or packaging with at least one LED module according to claim 1.

18. An electronic system with an electronic unit and a paper, plastic or a textile according to claim 13 or a document of value or security document according to claim 15, or a movable good according to claim 17, wherein the electronic unit comprises a primary resonant circuit for exciting the resonant circuit of the at least one LED module in order to check the authenticity of the paper, plastic, textile or of the document of value or security document or of the movable good by exciting the resonant circuit and the light then emitted by the LED module.

19. The electronic system according to claim 18, wherein the electronic unit is configured to detect a pulse response of the LED module and to check for a sufficient match with first reference data, and to excite the primary resonant circuit for excitation of the resonant circuit for operation of the LED module, such that the LED module lights up, only on the precondition that there is a sufficient match.

20. The electronic system according to claim 18, wherein the electronic unit comprises an optical sensor in order to sense the light emitted by the LED module and to compare it with second reference data, wherein, on the precondition that there is a sufficient match with the reference data, a signal is generated, which signals the authenticity of the LED module.

Description

[0048] Embodiments of the invention will be explained in greater detail hereinafter with reference to the drawings, in which:

[0049] FIG. 1 shows an embodiment of an electronic system according to the invention,

[0050] FIG. 2 shows a plan view of an embodiment of an LED module according to the invention,

[0051] FIG. 3 shows a sectional view of the embodiment according to FIG. 2,

[0052] FIG. 4 shows an exploded view of an embodiment of a piece of jewelry according to the invention,

[0053] FIG. 5 shows a sectional view of an embodiment of a paper, plastic or textile material according to the invention.

[0054] FIG. 6 shows a plan view of an alternative embodiment of an LED module according to the invention,

[0055] FIG. 7 shows a sectional view of the embodiment according to FIG. 6,

[0056] FIG. 8 shows a plan view of an alternative embodiment of an LED module according to the invention,

[0057] FIG. 9 shows a sectional view of the embodiment according to FIG. 8.

[0058] Elements of the following embodiments which correspond to one another or which are the same as one another are denoted by the same reference signs in each case.

[0059] FIG. 1 shows an embodiment of an electronic system 100 according to the invention. The electronic system 100 contains at least one LED module 102, which can be arranged in or on a movable good 104.

[0060] The LED module contains a circuit with an LED 106 and a resonant circuit which is formed by an inductor 108 and a capacitor 110, wherein the capacitor 110 is connected here in parallel with the LED 106 so that the total capacitance of the resonant circuit is given by the sum of the capacitor 110 and the capacitance of the LED 106. The resonance frequency of the resonant circuit is determined by this total capacitance and the inductor 108.

[0061] The circuit is fully encapsulated in the LED module 102 and is formed without connections. The only possibility for controlling the LED is to couple energy into the resonant circuit inductively so that the LED 106 lights up. For this purpose, the electronic system 100 has an electronic unit 112, which has field generation means, that is to say a primary resonant circuit 114, in order to excite the resonant circuit of the LED module 102. The primary resonant circuit 114 is preferably tailored to the resonant circuit of the LED module 102, that is to say the excitation occurs at the resonance frequency.

[0062] By way of example, the electronic unit 112 can be a point-of-sale terminal, as is used for example in the retail sector, for example in a supermarket. If the movable good 104 for example is a payment means, such as a banknote or a chip card, an authenticity check can be carried out at the point-of-sale terminal in that the point-of-sale terminal couples electrical energy into the resonant circuit so that the lighting-up of the LED signals the authenticity.

[0063] The electronic unit can also be a mobile radio unit, for example what is known as a smartphone, with an RFID or NFC interface, which performs the function of the primary resonant circuit 114. Alternatively, the electronic unit 112 can also be a contactless chip card terminal, for example with an NFC and/or RFID interface.

[0064] The LED module 102 can have a miniaturised design. By way of example, the thickness of the LED module 102 can be between 30 μm and 5000 μm and it can have lateral dimensions of, for example, 500 μm.Math.500 μm up to 3 mm.Math.3 mm.

[0065] The electronic unit 112 by way of example can be a battery-operated portable unit, for example a smartphone or a tablet PC. An application program, that is to say what is known as an app 156, is installed on the electronic unit 112 and can be started by a user via a user interface of the electronic unit, such as a touch-sensitive display, that is to say what is known as a touch panel 160. The electronic unit 112 can also have an optical sensor, such as a camera 158.

[0066] By way of example, the following approach is adopted in order to check the LED module 102: [0067] 1. The user starts the app 156. The app 156 then controls the primary resonant circuit 114 to send a pulse. This pulse can be what is known as a unit pulse, which is also referred to as a Dirac pulse. [0068] 2. The LED module 102 uses its antenna 118 to receive the pulse from the electronic unit 112. The circuit of the LED module 102 responds to this pulse with a pulse response, which is characteristic for the transfer function and therefore the resonance frequency of the LED module 102. This pulse response is sent from the antenna 118 and is received by the electronic unit 112 with the aid of the primary resonant circuit 114. [0069] 3. The electronic unit 112 has a memory, in which first reference data for the pulse response are stored. The app 156 accesses this memory in order to read the reference data and in order to check the received pulse response for a match with the reference data. If there is a sufficient match, the app 156 controls the primary resonant circuit 114 such that this excites the resonant circuit of the LED module 102 with the resonance frequency thereof. [0070] 4. The app 156 then controls the camera 158 so that the light emitted by the LED 106 on account of the coupling-in of energy is sensed. [0071] 5. Second reference data for the sensed light are stored in the memory of the electronic unit 112. The app 156 accesses this reference data in order to compare the sensed light with the reference data. In the event of a sufficient match, the LED module 102 is considered to be valid and the app 156 generates a corresponding signal, which for example is output from the electronic unit 112 as an optical signal on the touch panel 160 and/or as an acoustic and/or as a haptic signal, that is to say as a vibration signal, so that the user is informed of the successful check of the validity of the LED module 102.

[0072] The movable good 104 can be a document of value or a security document. The movable good 104 can be a protected data memory 170, in which personal data of a user are stored, for example, as is the case for example with an electronic personal ID card in the Federal Republic of Germany. The movable good 104 can also comprise a processor 172, which is configured to allow external access to the data memory 170 via communication interface 174 only if a cryptographic protocol for authentication and/or authenticity check of an external reader, for example the electronic unit 112, has been carried out successfully. This can be, for example, what is known as a basic access control (BAC) and/or an extended access control (EAC). The communication interface 174 can be formed as a contactless interface, for example as an RFID or NFC interface. The LED module is electrically connected neither to the processor 172 nor to the communication interface 174.

[0073] FIG. 2 shows a plan view of an embodiment of an LED module 102 according to the invention. The LED module 102 has a substrate 116, for example made of ceramic or plastic, such as polyimide or polyamide. An antenna 118 is arranged on the substrate 116, in that an antenna conductive track 120 is arranged on the substrate 116 in a plurality of windings.

[0074] The windings of the antenna conductive track 120 run along an edge region of the substrate, such that an antenna coil is formed as a result, which has a coil opening 122 in a central region of the substrate 166. An electrode 124 (see FIG. 3) of the LED 106 is arranged in the region of this coil opening 122.

[0075] The electrode 124 fills the coil opening 122 on the substrate 116 completely or partially. A first end of the antenna conductive track 120 is electrically connected to the electrode 124. The other end of the antenna conductive track is electrically connected to a second electrode 128 of the LED 106 by means of a via 126.

[0076] By way of example, the LED 106 has a first protuberance 130 for connection to the electrode 124 and a second protuberance 132, which is preferably arranged at the edge of the LED 106, so as to provide the largest possible discharge area for the emission, wherein the second protuberance 132 serves for the electrical connection to the second electrode 128.

[0077] The second electrode 128 has a first protrusion 134, which extends within the coil opening 122, in order to electrically connect a second electrode 128 to the protuberance 132. The second electrode 128 also has a flat region 136, which extends over the coil opening 122 and covers this and the first electrode 124 arranged there-beneath completely or partially. The electrode 128 also has a second protrusion 138, which connects the flat region 136 to the via 126, wherein the protrusion 138 extends over the antenna windings formed by the antenna conductive track 120.

[0078] In the case of the embodiment considered here, a first layer of the LED module 102 is formed by the substrate 116. The following second layer 140, besides the LED 106, also contains a dielectric, that is to say a material having a high relative permittivity, such as benzocyclobutene (BCB) or another polymer, which is filled with inorganic substances, such as ormocers and/or inorganic substances, such as titanium dioxide, barium titanate or lead zirconium titanate.

[0079] In an alternative embodiment (see embodiment in FIGS. 6, 7 and 8 and 9), the substrate 116 can function itself as dielectric, wherein the electrode 124 and the antenna conductive track 120 are arranged on one side of the substrate the electrode 128 is arranged on the opposite side of the substrate and the via 126 runs through the substrate, wherein the LED 106, depending on the embodiment, can be arranged on one side or the other side of the substrate or in a cavity or an opening in the substrate.

[0080] In accordance with the embodiment according to FIG. 2 and FIG. 3, the second layer 140 is followed by a third layer 142, specifically a cover layer, which closes off the LED module 102 outwardly and in particular covers the electrode 128 and the LED 102. The LED module 102 is thus completely encapsulated towards the outside, such that none of the components of the circuit formed in the LED module are accessible from outside without destroying the LED module, unless energy is coupled into the resonant circuit of the circuit inductively and contactlessly.

[0081] The substrate 116 for example has a thickness of from 10 μm to 50 μm. The metallisation layer applied to the substrate 116, by means of which layer the electrode 124 and antenna conductive path 120 are formed in particular, has a thickness for example of from 1 to 6 μm, for example 3 μm. The subsequent layer 140 with the dielectric and the LED 102 has a thickness by way of example of from 5 μm to 50 μm, and the cover layer, that is to say the layer 142, has a thickness of from 10 μm to 50 μm, for example.

[0082] The layer 142 for example can consist of an epoxy material. The layer 142 at least in the region of the light path of the light 144 emitted by the LED 106, can also contain one or more optically effective materials 146, which serve to provide an additional security feature and/or decorative effect and/or which can provide the emitted light 144 with additional information.

[0083] The LED module 102 can be produced using structuring techniques known per se.

[0084] A capacitance is formed by the electrodes 124 and 128 arranged opposite one another and the dielectric of the layer 140 disposed therebetween, which capacitance enters the capacitor 110. The parasitic capacitance of the antenna 118, which is caused primarily by the antenna windings of the antenna conductive track 120 running parallel to one another, also enters this capacitor 110.

[0085] Depending on the embodiment, the parasitic capacitance of the antenna 118 can be sufficient to reach a desired resonance frequency of the resonant circuit of the LED module 102, such that the flat region 136 can be omitted completely or partially. In this case, a further miniaturisation of the LED module 102 is made possible.

[0086] If the width of the antenna conductive track 120 is for example 10 μm and the distance 148 between two adjacent windings of the antenna conductive track 120 is for example 10 μm and the area of the substrate 116 by way of example is 2 mm.Math.2 mm, this thus gives, with a number of 40 antenna windings, an inductor 108 of 1.8 pH, such that a capacitor 110 of 76 pF is necessary in order to arrive at a desired resonance frequency of 13.56 MHz. In this case the design of the electrode 128 with the flat region 136 is preferred in order to reach this total capacitance 110.

[0087] If, by contrast, the substrate 106 has a size of merely 3 mm.Math.3 mm for example and the width of the antenna conductive track 120 is reduced for example to 5 μm and the distance 148 is reduced to 5 μm, an inductor of 10.6 pH is thus provided, in the case of a winding number of 46. In this case the parasitic capacitance of the antenna 118 together with the capacitance of the LED 106, which for example is 13 pF, is sufficient to bring the resonant circuit of the LED module 102 to the resonance frequency of 13.56 MHz.

[0088] In accordance with further embodiments of the invention it is possible to provide the circuit of the LED module 102 with more than one LED, for example anti-parallel LEDs, so as to hereby create a higher capacitance 110 with a smaller antenna coil, so as to thus enable even smaller external dimensions of the LED module 102.

[0089] FIG. 4 shows an embodiment of a piece of jewelry according to the invention with a mount 150 for a decorative element 152, for example a crystal, for example a polished crystal glass precious stone or semi-precious stone, a pearl, or another decorative element. At least one LED module 102 is arranged on the decorative element 152 or the mount 150.

[0090] By way of example, the decorative element 152 is transparent or semi-transparent, so that light emitted by the LED module 102 can pass through the decorative element 152, such that the decorative element 152 lights up if energy is coupled inductively into the LED module 102. In this case the LED module 102 is preferably arranged beneath the decorative element 152 in the mount 150, which for example can be formed as a prong setting. Alternatively, the decorative element 152 is fixed by adhesive bonding or magnetic holder.

[0091] FIG. 5 shows a cross-section through a material layer 154. The material layer 154 can be, for example, a paper, in particular for the production of banknotes or other documents of value or security documents. A plurality of LED modules 102 is arranged in a distributed manner in the material layer 154 and is completely embedded in the material layer 154. This can be achieved by adding the LED modules 102 to the pulp or to the paper web, when this is not yet dry or not yet fully dry, during the paper production process. The LED modules 102 are preferably coated beforehand with an adhesive, which cures following the addition to the pulp or paper web so as to thus form a particularly close bond with the surrounding paper.

[0092] The material layer 154 for example can also be a plastic, in particular a plastic film, as is also used in the production of documents of value or security documents, in particular in the production of chip cards. In this case, in order to produce the material layer 154, the LED modules 102 are added to the already plasticised plastic in order to then form the material layer 154 by a plastic injection-moulding or extrusion step, said material layer then solidifying with the LED modules 102 enclosed therein.

[0093] The material layer 154 for example can also be the wall of a component, such as the wall of a movable good, in particular for example of a movable good which consists wholly or partially of plastic, for example a drinks bottle, or a piece of jewelry.

[0094] FIGS. 6 and 7 show an embodiment of the invention in which the connections of the LED 106, that is to say the protuberances 130 and 132, are arranged on the same side of the LED 106. In this embodiment the first electrode 124 is formed by the two electrode portions 124.1 and 124.2, which are connected to one another by means of a via 168, which runs through the layer 140. Here, the antenna portion 124.1 is arranged within the coil opening 122 and fills this opening completely or partially, as is also the case in accordance with the embodiments according to FIGS. 2 and 3. As a result of the mutually opposed electrode 128 and the electrode portion 124.1 with the layer 140 arranged therebetween, said layer forming a dielectric, a capacitance is formed, which enters the capacitor 110 of the circuit.

[0095] In contrast to the embodiment according to FIGS. 2 and 3, the layer 140 in the case of the embodiment considered here has a dual function, specifically the function of the substrate and the function of a dielectric. An even smaller overall height can be attained as a result. The complete encapsulation of the LED module 102 in the embodiment according to FIG. 7 can be achieved in that a layer 142 is also applied to the underside, or in that the LED module 102 is embedded in a material layer 154 (see FIG. 5).

[0096] FIGS. 8 and 9 show an embodiment of the LED module 102 in each of which an antenna conductive track 120.1 runs on the upper side of the layer 140 and an antenna conductive track 120.1 runs on the rear side of the layer 140, such that the layer 140 lying between the antenna conductive tracks 120.1 and 120.2 acts as a dielectric with regard to the parasitic capacitance of the mutually opposed antenna conductive tracks. In this embodiment the connections, that is to say the protuberances 130 and 132 of the LED 106, are again arranged on the same side.

[0097] The protuberance 130 is connected to the antenna conductive track 120.1, which is connected to the antenna conductive track 122.2 by means of a via 126. The end of the antenna conductive track 120.2 is connected to the other protuberance 132 of the LED 106 by means of a further via 168. By means of this arrangement of the antenna 118, a relatively large parasitic capacitance is generated, such that the flat region 136 or a flat design of the electrode 124 or of the electrode portion 124.1 can be omitted here completely or partially.

LIST OF REFERENCE SIGNS

[0098] 100 electronic system [0099] 102 LED module [0100] 104 movable good [0101] 106 LED [0102] 108 inductor [0103] 110 capacitor [0104] 112 electronic unit [0105] 114 primary resonant circuit [0106] 116 substrate [0107] 118 antenna [0108] 120 antenna conductive track [0109] 122 coil opening [0110] 124 electrode [0111] 126 via [0112] 128 electrode [0113] 130 protuberance [0114] 132 protuberance [0115] 134 protrusion [0116] 136 flat region [0117] 138 protrusion [0118] 140 layer [0119] 142 layer [0120] 144 light [0121] 146 material [0122] 148 distance [0123] 150 mount [0124] 152 decorative element [0125] 154 material layer [0126] 156 app [0127] 158 camera [0128] 160 touch panel [0129] 168 via [0130] 170 memory [0131] 172 processor [0132] 174 communication interface