HERMETIC HOUSING AND ELECTRONICS PACKAGE FOR AN IMPLANT DEVICE

Abstract

The present invention relates to a hermetic package (40) suitable to be implanted in a body of an animal or a human patient. The housing (40) comprises a base part (50), a cover part (60) suitable to cover the base part (50), and a connecting means (70), provided at an interface between the base part (50) and the cover part (60). The base part (50) comprises a first hermetic material and the cover part comprises a second hermetic material and the connecting means (70) comprise a third hermetic material, adapted to hermetically seal the interior of the hermetic housing (40) from the outside of the hermetic housing (40). The present invention further refers to an implantable electronics package with such a housing, an implant, in particular a retinal implant, and a method to provide a hermetic housing for an implant.

Claims

1. An hermetic housing that is configured to be implanted in a body of an animal or a human patient, the housing comprising: a base part; a cover part configured to cover the base part; and a connecting means, provided at an interface between the base part and the cover part, wherein the base part comprises a first hermetic material and the cover part comprises a second hermetic material, wherein the connecting means comprises a third hermetic material, adapted to hermetically seal an interior of the hermetic housing from an outside of the hermetic housing.

2. The hermetic housing according to claim 1, wherein the cover part comprises a material, which is transparent to at least a predetermined wavelength or wavelength range, and wherein the material is a metal-free material.

3. The hermetic housing according to claim 1, wherein the base part comprises a ceramic material.

4. The hermetic housing according to claim 1, wherein the connecting means comprises a metal-free solder paste.

5. The hermetic housing according to claim 4, wherein the cover part comprises a material that is transparent to a predetermined wavelength or wavelength range, wherein the solder paste is light absorbent for the predetermined wavelength or wavelength range, or wherein the solder paste is light-absorbent at least for one wavelength or a part of the wavelength range, for which the cover part of the hermetic housing is transparent.

6. An electronics package for an implant device, the electronics package comprising at least one receiving unit; an electrical circuit adapted to generate a stimulating signal; and a first hermetic housing, wherein the first hermetic housing comprises: a base part adapted to receive the electrical circuit and/or the at least one receiving unit; a cover part, adapted to cover the base part; and a connecting means, provided between the base part and the cover part, adapted to connect the base part and the cover part and to hermetically seal an interior of the hermetic housing from an exterior of the hermetic housing.

7. The electronics package according to claim 6, wherein the electronics package comprises a second hermetic housing arranged at least partially around the first hermetic housing.

8. The electronics package according to claim 6, wherein at least one transmitting and/or receiving unit is provided outside the first hermetic housing and inside the second hermetic housing.

9. The electronics package according to claim 6, wherein the second hermetic housing comprises a biocompatible material that includes, silicone.

10. The electronics package according to claim 6, wherein the base part comprises a bottom part, the bottom part comprising a stack of layers, wherein at least one of the layers in the stack of layers comprises an integrated electrical circuit.

11. A prosthesis system comprising: a first implantable device comprising an electronics package, the electronics package comprising: at least one receiving unit an electrical circuit adapted to generate a stimulating signal; and a first hermetic housing, wherein the first hermetic housing comprises: a base part adapted to receive the electrical circuit and/or the at least one receiving unit a cover part, adapted to cover the base part; and a connecting means, provided between the base part and the cover part, adapted to connect the base part and the cover part and to hermetically seal an interior of the hermetic housing from an exterior of the hermetic housing; a second implantable device that is adapted to be implanted into an organ of a patient, and that is connected with the electronics package.

12. The prosthesis system according to claim 11, wherein the second implantable device comprises at least one stimulating electrode configured to stimulate living tissue or cells.

13. The prosthesis system according to claim 11, wherein the second implantable device comprises a receiving coil, which is connected to a transmitting coil of the electronics package.

14. The prosthesis system according to claim 11, wherein the prosthesis system comprises an extracorporeal component that includes: a first transmitting unit; and a signal generation unit adapted for generating a signal and applying the signal to the first transmitting unit, wherein the first transmitting unit is adapted for transmitting the signal generated by the signal generation unit to the electronics package.

15. A method for providing an implantable electronics package suitable to be implanted in a body of an animal or a human patient comprising: providing a base part of a hermetic housing adapted to receive an electrical circuit and/or at least one receiving unit; providing an electrical circuit and/or at least one receiving unit on a bottom part of the base part; providing, on a surface of the base part, a connecting means; providing, on the connecting means, a cover part; connecting the cover part with the base part and hermetically sealing a gap between the cover part and the base part by light induced heating of the connecting means, such that an interior of the hermetic housing is hermetically sealed from the an exterior of the hermetic housing.

16. The method according to claim 15, wherein the connecting means comprises a glass solder paste, and wherein connecting the cover part with the base part comprises laser-soldering of the solder paste.

17. The method according to claim 16, further comprising pre-curing the solder paste onto the base part of the hermetic housing.

18. The method according to claim 15, further comprising controlling a light of a laser to heat an interface area between the cover part and the base part covered with the connecting means, wherein a light intensity of the light is increased and decreased linearly at least around a desired target intensity at a predetermined target point or target area at the interface between the cover part and the base part.

19. The hermetic housing according to claim 3, wherein the ceramic material is a metal-free ceramic material or wherein the base part comprises a plurality of ceramic layers that include layers of low temperature, co-fired ceramic (LTCC).

20. The hermetic housing according to claim 2, wherein the metal-free material includes metal-free glass.

Description

[0060] Further details, preferred embodiments and advantages of the present invention will be found in the following description with reference to the drawings, in which:

[0061] FIG. 1 gives an overview of a visual prosthesis system;

[0062] FIG. 2 shows a cross section of an eyeball comprising a retina implant;

[0063] FIG. 3 shows (a) a side view of a hermetic housing according to an embodiment of the present invention and (b) a magnification of a portion of the side view according to (a);

[0064] FIG. 4 shows a base part of a hermetic housing according to an embodiment of the present invention comprising a multiple layer structure in an explosive view;

[0065] FIG. 5 shows a top view of a hermetic housing according to an embodiment of the present invention.

[0066] FIG. 1 shows as an Example a visual prosthesis system for at least partially reestablishing a modest visual perception and a sense of orientation for blind and visually impaired users. There exist a variety of different diseases of the retina that are caused by a degeneration of the photosensitive cells of the retina. Examples for degenerative diseases are retinitis pigmentosa, macula degeneration or Usher syndrome. As a result of these regenerative diseases, people slowly lose their vision and eventually suffer from complete blindness.

[0067] The visual prosthesis system shown in FIG. 1 comprises a retinal implant 1 that may for example comprise an intraocular part located within the eyeball 2 and an extraocular part located at the outer surface of the eyeball 2. The intraocular part of the retinal implant 1 comprises an array of micro-contacts that is in direct contact with the patient's retina, wherein the micro-contacts are adapted for electrically contacting the retinal tissue.

[0068] The visual prosthesis system further comprises a visual interface 3, which may for example be realized as an eyeglass frame. The visual interface 3 is adapted for supplying energy to the retina implant 1, and for performing wireless data communication with the retina implant 1.

[0069] The energy transfer from the visual interface 3 to the retina implant 1 is effected by a first transmission coil 4 and a second transmission coil 5 which are both integrated in the eyeglass frame 21, e.g, a temple arm 9. The visual prosthesis system as shown according to the embodiment of FIG. 1 comprises a pocket computer 6 that is connected to the visual interface 3 via a wire connection 7. The pocket computer 6 comprises a signal generation unit 8 that generates a first high frequency signal for the transmission coil 4 and a second high frequency signal for the second transmission coil 5. Preferably, the two high frequency signals have the same frequency, with the frequency of the first and the second high frequency signal being in the range between 100 kHz and 100 MHz. Further preferably, the second high frequency signal is phase shifted relative to the first high frequency signal. In alternative embodiments, only one transmission coil and, hence, one high frequency signal may be provided.

[0070] Via the wire connection 7, the first high frequency signal is supplied to the first transmission coil 4, and the second high frequency signal is supplied to the second transmission coil 5.

[0071] The first transmission coil 4 transmits the first high frequency signal, and the second transmission coil 5 transmits the second high frequency signal. The first and the second transmission coil 4, 5 radiate an electromagnetic field having a frequency in the radio frequency range.

[0072] The retina implant 1 comprises a receiver coil for receiving the electromagnetic field generated by either the first transmission coil 4 or the second transmission coil 5, or both. The electromagnetic signal received by the receiver coil provides the electrical power for operation of the retina implant 1.

[0073] The visual interface 3 may further comprise a video camera 10 for acquiring a video image of the patient's field of view. Video signals acquired by the video camera 10 are transmitted to the pocket computer 6. There, the video signals are converted into corresponding stimulation data for the array of micro-contacts on the retina implant 1. The stimulation data determined by the pocket computer 6 is forwarded to the visual interface 3 and transmitted to the retina implant 1. Alternatively, integrated circuits may be provided, which are enabled to convert the received video signals into stimulating pulses. Accordingly, the pocket computer may also be replaced by a computer or computer chip integrated in at least one of the prosthesis devices, implantable or external to a body. Further, the video signal may be transmitted to a remote computer or computing device, including, for instance a cell phone or a standalone unit. The transmission may in particular be wireless, in order to omit any wire connection affecting a wearing comfort.

[0074] For transmitting the stimulation data to the retina implant 1, there exist different alternatives. According to one embodiment, the stimulation data is modulated onto at least one of the first and/or the second high frequency signal. At the retina implant, the received electromagnetic signal is demodulated. In this embodiment, the first and/or the second high frequency signal are used both for data communication and for transferring energy to the retina implant 1.

[0075] According to another embodiment, the stimulation data is transmitted to the retina implant 1 via a modulated light beam, preferably via modulated infrared light. In this embodiment, the first and/or the second high frequency signals are solely used for transferring energy to the retina implant 1.

[0076] At the retinal implant 1, the stimulation data is decoded. In accordance with the stimulation data, stimulation pulses are applied to the micro-contacts of the retina implant 1. The stimulation of the retinal tissue causes a visual impression.

[0077] FIG. 2 shows a cross section of a patient's eye comprising a retinal implant. External light passes the cornea 11 and the eye lens 12 and strikes the retina 13. The retina 13 covers a large part of the eyeball's interior. The eyeball's outer surface is formed by the sclera 14. Between the retina 13 and the sclera 14, a choroid membrane 15 is located. The iris 16 determines the amount of light that may enter into the interior of the eye. The eye lens 12 is fixed by the ciliary muscle 17.

[0078] The retina implant according to the embodiment shown in FIG. 2 comprises an intraocular part 18 and an extraocular part 19. The intraocular part 18 is located in the interior of the eye, whereas the extraocular part 19 is fixed to the outer surface of the sclera 14. In the embodiment shown in FIG. 2, the intraocular part 18 and the extraocular part 19 are electrically connected by wire connections 20 that pass through the sclera 14 at a position right behind the ciliary muscle 17. Alternatively, the intraocular part 18 and the extraocular part 19 may be connected wirelessly.

[0079] The patient wears an eyeglass frame 21 with glasses 22. A first transmission coil 23 is arranged around one of the eyeglasses. A second transmission coil 24 is integrated in one of the temples 25 of the eyeglass frame 21. That way, the transmission coils have an angular arrangement with respect to another. The first transmission coil 23 is adapted for transmitting a first high frequency signal, and the second transmission coil 24 is adapted for transmitting a second high frequency signal. The electromagnetic field generated by the first transmission coil 23 is superposed with the electromagnetic field generated by the second transmission coil 24. The extraocular part 19 of the retina implant comprises a receiver unit, here a receiver coil 26. The receiver coil 26 is adapted for receiving the superposed electromagnetic signal and for supplying electrical power to the components of the retina implant. Energy transfer from the first and/or the second transmission coil 23, 24 to the receiver coil 26 can be optimized by adjusting the relative phases and the respective amplitudes of the first and the second high frequency signal. Thus, the superposed electromagnetic field can be adjusted to the orientation of the receiver coil 26 in some embodiments of the present invention.

[0080] Additionally, stimulation data carrying visual information has to be transmitted from the visual interface to the retina implant. In the embodiment depicted in FIG. 2, a modulated infrared beam 27 is used for transmitting the stimulation data to the retina implant. The infrared beam 27 may for example be generated by an infrared transmitter LED located in the vicinity of the glasses 22. The modulated infrared beam 27 passes through the eye lens 12 and strikes an optical receiver element 28 (e.g. a photodiode) located on the intraocular part 18 of the retina implant. The stimulation data received by the optical receiver element 28 is forwarded via the wire connection 20 to a retina stimulation chip 29 located on the extraocular part 19 of the retina implant, i.e. in a hermetic housing 40 of the retinal implant. Preferably, the retina stimulation chip 29 is implemented as a digital signal processing chip. The retina stimulation chip 29 is operative to convert the stimulation data into corresponding stimulation pulses for an array 30 of micro-contacts located directly on the retina 13. The stimulation pulses are supplied to the array 30 of micro-contacts via the wire connection 20. The micro-contacts are adapted for stimulating the ganglia of the retina 13, and this stimulation causes a visual impression.

[0081] According to an alternative embodiment, instead of transmitting the stimulation data to the retina implant via a modulated infrared beam 27, the stimulation data may be modulated onto at least one of the first and the second high frequency signal. According to this embodiment, the first and the second high frequency signal are adapted both for transferring energy and for transmitting the stimulation data to the retina implant.

[0082] The receiver coil 26 and the stimulation chip 29 arranged extraocular as shown in FIG. 2 are provided in a hermetic housing 40, in order to reduce any degenerative effects on the electronics. According to the definition of the term hermetic given above, the hermetic housing 40 fulfills at least the standards of hermeticity as set out above, e.g. the MIL-STD-883H Method 1014-standard.

[0083] It will also be noted that according to alternative embodiments, an additional transmitting and/or receiving unit, in particular at least one coil, may be provided within the hermetic housing 40. Further, additional or alternative electronic components may be provided within the hermetic housing 40 without departing from the scope of the invention to provide a hermetic housing for an implant.

[0084] FIG. 3 shows in its sub-figure (a) a side view of the hermetic housing 40 according to an embodiment of the present invention. The housing 40 comprises a base part 50, a cover part 60, such as a lid or a frit, and a connecting means 70. The connecting means 70 is provided between the base part 50 and the cover part 60 and is suitable to hermetically seal the gap between the cover part 60 and the base part 50.

[0085] The sub-figure (b) of FIG. 3 shows a magnified view of an edge portion of the housing 40 as indicated by the ellipse in FIG. 3(a). The base part 50 of the housing 40 in the embodiment according to FIG. 3 comprises a layer structure. The layer structure therein comprises at least an outer bottom layer 56. The outer bottom layer 56 is the outermost layer, which may therefore enable a contact to the outside of the hermetic housing, as will be discussed with respect to FIGS. 4 and 5. On top of the outer bottom layer, multiple intermediate layers 53 may be provided. As an innermost layer defining a bottom of a cavity of the housing 40, an inner bottom layer 54 is provided.

[0086] On top of the inner bottom layer 54, in the embodiment of FIG. 3, a plurality of wall layers is provided, comprising a top wall layer 52. As may be seen in FIG. 4, the wall layers are ring-like shaped, forming a cylindrical cavity on the inner bottom layer, when stacked onto another. Electrical components to be protected by the hermetic housing may be placed within that cavity.

[0087] On top of the top wall layer 52, the connecting means 70 is provided as an additional layer. The cover part is placed on the top wall layer 52, thus sandwiching the connecting means between the cover part 60 and the base part 50.

[0088] As previously indicated, the cover part may comprise glass. In particular, the cover part may comprise a glass which is transparent to light, e.g. infrared light of the near infrared range. The cover part accordingly may be transparent to more than 90% of incident light of a near-infrared wavelength, e.g. between 800 and 940 nm. Further, in order to limit the size of the housing, which may serve as part of an implantable device, the cover preferably has a thickness of less than 1 mm, preferably less than 500 m, more preferably of 400 m or less.

[0089] On the other hand, in order to provide sufficient resistance during the hermeticity test, when the cover part is exposed to mechanical stress, e.g., due to application of a vacuum, the cover part needs to be solid enough to withstand that stress. Accordingly, the cover part may have a thickness of more than 200 m, preferably of more than 300 m. Most preferably, the cover part has a thickness of between 300-350 m or between 370-430 m. As one alternative for such a cover, a thin glass, e.g. comprising borosilicate glass, may be chosen. Alternative cover parts may comprise alternative materials without departing from the scope of the present invention, such as soda lime glass, quartz or vycor, among others.

[0090] In some embodiments, as for instance shown in FIG. 3, the cover part 60 on top of the base part 50 may comprise a beveled edge around a circumference of the cover part 60. The bevel angle preferably is within the range of about 60-80, preferably 70-90, particularly, the bevel angle is 70 and more particularly the bevel angle is 80. Such a slanted edge may reduce the risk of damaging tissue or devices due to a sharp edge.

[0091] FIG. 4 shows an exploded view of the base part 50 of the hermetic housing 40. The bottom layers 56, 53, 54 provide a bottom seal of the hermetic housing 40. Each layer may comprise a ceramic material, such as a low temperature co-fired ceramic (LTCC). The bottom layers 56, 53, 54 comprise metallizations and vias 57. In addition, the inner bottom layer 54 comprises electrical connections or connection pads 55. Electrical components, which are to be positioned within the housing 40, may be connected with the outside of the housing 40 by contacting the contact pads 55 and contacting through the metallizations and vias. The metallizations may for instance comprise gold. The contacts 55 on the inner bottom layer 54 may for instance comprise AgPd. The ring-like wall layers with the top wall layer 52 are provided without metallization.

[0092] On top of the top wall layer, the connecting means 70 is provided as a ring like layer. The inner diameter of the connecting means layer corresponds to the inner diameter of the ring-like top wall layer. In particular embodiments, during production of the base part 50 of the hermetic housing 40, the connecting means 70 is a solder paste, which is printed on the top wall layer 52.

[0093] In the particular embodiment of FIG. 4, the base part comprises a total of ten LTCC layers. The bottom four layers, including the outermost bottom layer 56, intermediate layers 53, and the innermost bottom layer 54, comprise metallizations and vias for contacting electrical components and providing electrical connections to the outside of the housing 40. The remaining six layers comprising the top wall layer 52 are provided to form the wall, or rim, of the housing 40. It will be noted however, that the number of layers for the bottom part of the base part 50 as well as the number of layers for the wall part of the base part 50 may differ from the above example. In particular, the number of layers depends on factors such as thickness, hermeticity of the respective layer, metallizations and via-sizes, intended heremticity, and others. In order to provide a hermetic sealing of the bottom of the housing 40, i.e., the four bottom layers according to FIG. 4, a total thickness of 500 m may be sufficient to hermetically seal the housing. Depending on the hermetic standards, which shall be applied, the thickness may also be below or above 500 m, as well.

[0094] In order to provide a cavity of sufficient size, the wall layers may have a total thickness, i.e. a height of the cylindrical cavity, of about 1200 m. Again, depending on the specific application, the total height of the wall layers, i.e. the cavity, may be below or above 1200 m, as well.

[0095] The connecting means 70, here a glass solder paste, is printed on top of the top wall layer 52. That solder paste may be a lead-free solder, such as SnBi-solder or, in particular, be a solder paste available under the trading name Glass Solder Ferro DL 11-205. Alternative solder materials may be used without departing from the scope of the present invention. In particular, lead-free, and, generally, metal-free solder pastes may be preferable.

[0096] During production of the base of the hermetic housing, the individual layers may be laminated and fired, in order to provide a tight and hermetic bond. In order to hermetically seal the base part 50 with the cover part 60, the connecting means 70, i.e. a heat-curable solder paste, is provided between the cover part 60 and the base part 50. Prior to covering the base part 50 with the cover part 60, the desired electronic components are placed and connected within the hermetic housing 40. The cover part 60 is then placed on the base part 50 with the solder paste sandwiched there between. The solder paste is then heated by means of light, preferably laser light, directed on the interface between base part 50 and cover part 60. The solder paste is cured due to the application of energy by the laser and provides a hermetic seal between the base part 50 and the cover part 60. It is to be noted that the laser light has a wavelength in that frequency range, in which the cover part is transparent for the light and the solder paste is absorbent for the light.

[0097] In order to prevent the housing from heating up to an undesirable amount due to thermal conductivity from the interface between the cover part 60 and the base part 50 in response to laser application, the housing, i.e. the ceramic bottom layers of the base part, is placed on a cooling plate. The cooling plate typically is set at a temperature of about 100 C. in order to prevent heating of the entire device and particular the bottom part of the base part, where electronic devices may be connected, to temperatures induced by the light-application.

[0098] Further, in order to improve the sealing of base part 50 and cover part 60, a weight may be applied on the cover part, in order to increase the pressure of the cover part 60 on the base part 50 and the connecting means 70 placed there between. That may allow better distribution of the connecting means 70, i.e. the solder paste according to preferred embodiments of the present invention, and thus an increase in contact area between the solder and the cover part and/or the base part. Further, that may allow an increased hermetic sealing due to a better bonding between connecting means 70 and both, the cover part 60 and the base part 50.

[0099] FIG. 5 shows a top view of an assembled hermetic housing 40. From that top view, the ring-shaped top wall layer 52 is shown. At an inner diameter of the top wall layer 52, the connecting means 70, i.e. the solder paste, is provided as a ring structure, wherein the outer diameter of the connecting means 70 is smaller than the outer diameter of the top wall layer 52. The outer diameter of the connecting means 70 may also be smaller than the outer diameter of the cover part 60, which is not shown in FIG. 5. A cavity formed by the wall layers on the bottom of the cavity is confined by the inner bottom layer 54. Connecting pads 55 on the inner bottom layer 54 are provided, which allow connection with, e.g., a stimulation chip 29 or other electrical components.

[0100] In some embodiments, a transmitting and/or receiving unit, e.g., a coil, may also be provided in the cavity and on the inner bottom layer 54.

LIST OF REFERENCE SIGNS

[0101] 1 retinal implant [0102] 2 eyeball [0103] 3 visual interface [0104] 4 first transmission coil [0105] 5 second transmission coil [0106] 6 pocket computer [0107] 7 wire connection [0108] 8 signal generation unit [0109] 9 temple arm [0110] 10 video camera [0111] 11 cornea [0112] 12 eye lens [0113] 13 retina [0114] 14 sclera [0115] 15 choroid membrane [0116] 16 iris [0117] 17 ciliary muscle [0118] 18 intraocular part [0119] 19 extraocular part [0120] 20 wire connection [0121] 21 eyeglass frame [0122] 22 glasses [0123] 23 first transmission coil [0124] 24 second transmission coil [0125] 25 temples [0126] 26 receiver coil [0127] 27 infrared beam [0128] 28 receiver element [0129] 29 stimulation chip [0130] 30 array [0131] 40 hermetic housing [0132] 50 base part [0133] 52 top wall layer [0134] 53 intermediate layer [0135] 54 inner bottom layer [0136] 55 contacts/connection pads [0137] 56 outer bottom layer [0138] 57 metallizations and vias [0139] 60 cover part [0140] 70 connecting means