WO2008077914A2

WO2008077914A2 - Portable medical appliance with encapsulated function modules

Info

Publication number: WO2008077914A2
Application number: PCT/EP2007/064402
Authority: WO
Inventors: Maurice Ducret; Marco De Polo
Original assignee: Disetronic Licensing Ag
Priority date: 2006-12-27
Filing date: 2007-12-20
Publication date: 2008-07-03
Also published as: WO2008077914A3

Abstract

According to the invention, a medical appliance is created in which the structural groups (1, 2, 3, 4, 5, 6, 9) are held together and fixed relative to one another via a main structure. The structural groups or parts thereof are encapsulated with a material (8) having a certain softness, in order, on the one hand, to protect the structural parts from water and moisture and, on the other hand, to absorb impacts and vibrations acting on the structural parts. The main structure is an outer shell or a cover (10) which, for example, assumes the functions of impact toughness, additional impact attenuation and resistance to environmental influences.

Description

Portable medical appliance with encapsulated function modules

Description:

The invention relates to a portable medical appliance with encapsulated function modules and to a method for encapsulating structural groups of a medical appliance in order to create a housing that is water-tight and resistant to impacts.

In many portable medical appliances, stringent demands are placed on mechanical robustness and water- tightness, particularly in self-administration of medicaments, as is customary in the treatment of diabetes, for example. The administration devices are by now of such small dimensions that they can be worn in almost all situations encountered in life, for example when playing sports, when showering, and also in water. The water-tightness must be guaranteed under all circumstances and throughout the entire lifetime. Depending on the type of medical appliance, the lifetime is set at several months or even years. Water- tightness is problematic, because the housings of the administration devices are usually constructed in several parts and are provided with housing components that have to be accessible from the outside. The necessary water-tightness even has to be ensured after substantial mechanical loads, in particular after the effects of impacts. A further aspect concerns the surface quality of a portable medical appliance, which is intended to have a certain impact toughness throughout its lifetime and should provide protection against various environmental influences, for example salt water or sweat. The problems equally affect blood glucose meters that can be worn on the body as continuously measuring appliances and also the strip- type blood glucose meters in use under more difficult environmental conditions.

Connection by welding the housing or adhesive bonding with adhesive or sealing compound is known. A disadvantage of such housing connections is a lack of shock resistance to external forces or a lack of absorption of shock energy.

Numerous devices with a robust housing construction and a certain water-tightness are known in the prior art.

A portable medical appliance in the form of an insulin pump with selectively encapsulated electronics modules is known from the patent application US2002/0171297 Al. Ensuring absolute water-tightness is not a principal aim there. Instead, the selective encapsulation of the components is intended to achieve a differing degree of protection for the insulin pump components. In the event of contamination, or in the event of water penetrating into the housing interior, components of secondary importance for the safety of the patient are intended to fail first, before the modules with great patient risk switch off in a controlled way.

Known water-tight storage housings for infusion equipment designed for use in water do not, however, provide permanent protection against impact loads, can be operated only with difficulty in the receiving housing, and the displays are not easy to hear or see.

It is an object of the invention to create a robust housing for a portable medical appliance with sensitive function modules, to guarantee water-tightness and resistance to mechanical action and environmental influences, and additionally to guarantee ease of operation . This object is achieved by the subject matter of independent claim 1 and a method according to claim 29. Advantageous embodiments are set forth in the dependent claims .

The structural groups or parts of a medical appliance are encapsulated with a material having a certain softness, in order, on the one hand, to protect the structural parts from water and moisture and, on the other hand, to absorb impacts and vibrations acting on the structural parts. For this purpose, the hollow spaces present between the modules are at least partially filled.

The medical appliance can be a blood glucose meter for regularly determining blood glucose. The measurement is carried out to determine the blood glucose content of a blood sample that the diabetic patient has taken, the measurement being carried out optically or electrically, for example.

Another medical appliance in the form of an administration device, as concerned in the invention, comprises a housing, a seat formed in the housing for the product to be administered, and a discharge device for dosed delivery of the liquid medicament from the container, a device for driving the discharge device, a control unit for controlling the drive and for controlling the necessary operating and display means, in which the components are connected to one another via the main unit, and in which the hollow spaces present between the parts are at least partially filled with a compound.

In addition to its waterproofing properties, the encapsulating compound is characterized by good mechanical damping properties and vibration-absorbing properties. In order also to meet demands over the long term, the encapsulating compound is intended to have properties affording chemical resistance, a particular aim being to guarantee protection against sweat and salt water.

The requirements of the hardness of the encapsulating compound should lie in the range of 40 - 80 Shore. In order to still allow a reading to be taken in cases where optical display elements are encapsulated, an optical transmissivity of greater than 80%, relative to a wavelength of light of 400 - 700 nm, at a layer thickness of 10 mm must be ensured in the cured state. The requirement for good protection against moisture and wet means that the encapsulating compound has to cover the components with a water-tight protective layer. A suitable encapsulating compound is manufactured by the company Wacker under the trade name SiliGel®. The two-component silicone rubber, which can be cast at room temperature, vulcanizes to a soft gel- like vulcanizate and, because of the good mechanical damping properties and low modulus of elasticity, is suitable for protecting the components in the innermost housing area.

Another suitable encapsulating compound is a crosslinkable silicone compound or a vulcanizable rubber compound which, in the completely vulcanized state, connects the functional modules to the main structure with a force fit, a form fit or a cohesive material fit.

Another encapsulating compound material can consist of a gel-like compound or of a gel-like liquid that encloses or receives the functional modules. To permit a floating bearing, the gel-like compound or the liquid is to be enclosed by a suitable support, e.g. a closed housing or a pouch that prevents runout.

In enveloping of the components with the compound, while ensuring a minimal coverage of the components with encapsulating compound, suitable external shaping can provide a housing that can be optionally enclosed by a removable outer housing or what is called a cover.

If the housing interior is completely filled with the encapsulating compound - excluding the externally accessible areas such as the ampoule compartment - an accumulator element can be present as energy source in one embodiment according to the invention. The electrical energy accumulator can be charged by inductive, capacitive or galvanic coupling from a charging device arranged external to the housing. If a galvanic charge connection exists from the charging device to the energy accumulator, the contacts in one preferred embodiment are located in a cavity of the medical appliance, e.g. in the ampoule compartment open to the outside.

Hollow spaces can be structurally formed in the encapsulating compound, on the one hand in order to achieve a reduction in weight and, on the other hand, to compensate for a static imbalance.

Inside the housing of an administration device, the functional modules are connected by fluidic connections or by electrical connections. If the connection is effected by plug connections, plug connections are needed that can be cast in a vacuum-tight manner.

In another preferred embodiment, functional modules are combined in higher-order groups or multi-module units, by preliminary separate casting, and are then introduced and encapsulated in a separate compartment.

In a particularly preferred embodiment, the modules are positioned and held together by a framework structurally created in the appliance interior. The framework is stable against deformation, which means that substantial impact forces acting on the frame or static forces are taken up by same or have only a slight deforming effect. This kind of "reinforcement" has the result that there is only minimal loading of the highly sensitive components. The purpose of the framework is to enclose the whole inner area of the components to be protected in the form of a frame structure. If only individual components or functional modules are to be protected, the coverage of the frame structure can be limited to those components that are to be protected. A further improvement is achieved by using vibration-absorbing frame materials.

In another particularly preferred embodiment, the appliance contains means for visual, tactile and vibratory display of information. Good transmission of information can be achieved by means of a solid-borne sound coupling to the outside of the housing. Possible ways of conducting solid-borne sound, for example by introducing webs of high stiffness or by creating resonance bodies in the interior, are known to persons skilled in the art. If an alarm vibrator is provided in the medical appliance, it can be connected by a fixed brace to the other functional elements, wherein the oscillations are transmitted to the main compound, and the resulting improved transmission of solid-borne sound ensures improved perception.

In a particularly preferred embodiment, the main structure is composed of an outer shell or cover, which can assume for example the functions of impact toughness, additional impact absorption and resistance to environmental influences. By arrangement on the outside of the housing, suitable structural measures permit simple replacement if the outer shell no longer meets the aesthetic requirements as a result of wear or has only inadequate resistance to environmental influences . A method according to the invention for producing such a portable medical appliance consists of one or more shaped bodies which, during the encapsulating process, represent the structural groups protruding outwards with their free surfaces or are suitable, during the encapsulating process, for keeping free the space that is later occupied by the structural group.

Some operating and display elements of the administration device require a free outer surface with sealing to the inside. This can be achieved if, during the encapsulation, the surface that is to remain free is maintained free by covering it with a negative mould, for example.

Other preferred embodiments of the invention will become evident from the dependent claims and from the following description in which reference is made to the figures, of which:

Fig. 1 shows a general configuration of a medical appliance in the form of a device for administering liquid medicaments, with encapsulated components.

Fig. 2 shows a temporary cover of a structural group protruding outwards in use with a free surface during the encapsulating process.

Fig. 3 shows a temporary cover for creating a resonance chamber for an acoustic transmitter.

Fig. 4 shows the contacting of an outwardly protruding, water-tight piezo element.

Fig. 5 shows an embedded operating element or display element removed from the electronics module.

Fig. 6 shows a function module, e.g. of a vibrator, which requires a volume to be kept free in the interi or .

Fig. 7 shows an integrally cast outer element, e.g. in the form of an operating element.

Fig. 8 shows a water-tight component mounted directly on the housing.

Figure 1 shows an embodiment of a medical appliance in the form of a device for administering liquid medicaments. The components drive/motor (3), threaded rod/telescope (4) , ampoule compartment (5) , electronics

(2), battery compartment (1) form the main unit. To improve rigidity, the main unit can be held by individual support elements or by a support framework. Some or all of the main unit is encapsulated by a compound having a certain softness. The ampoule compartment (5) has an opening to the outside, such that ampoules can be replaced. This opening can be closed with an adapter (6) . A battery compartment (1) is similarly configured and is closed by a cap (7) . The main unit forms a kind of skeleton that receives and positions the structural groups and is made of a material that is solid and hard and, even with a small wall thickness in the mm range, forms a dimensionally stable structure, or the skeleton acts as a kind of reinforcement. The functional modules encapsulated with encapsulating compound (8) are completely enclosed in the main unit and, because of the requirements of a matching fit to the outer housing shell, the encapsulating compound can protrude above the main unit .

Figure 2 shows a temporary cover of a structural group protruding outwards with a free surface during use (11) in the encapsulating process. Some elements, e.g. keys, displays and acoustic alarm elements, demand a free surface or functional surface to the outside and at the same time demand sealing on the inside faces. A shaped body (13), with which the space later occupied by the structural group can be kept free during the encapsulating process, is provided, and, after removal of the shaped body, a recess is created for the structural groups protruding outwards with a free surface. In this way, the water-sensitive parts, e.g. the electrical contacts (12) that lead to the electronics, are protected by the encapsulating compound, and the functional surface remains visible and accessible. The shaped body can also extend into the inner area of the main unit.

Figure 3 shows an embodiment in which an acoustic signal transmitter, received in a water-tight manner, is provided with a resonance chamber (15), is encapsulated by the acoustic signal transmitter (14) and can be connected to the outer housing shell via a solid-borne sound coupling.

Figure 4 shows a variant solution using a water-tight piezo element (16) whose individual contacts (17) are sealed individually.

Figure 5 shows an encapsulated operating element or display element (20) removed from the electronics module, with a free surface facing outwards. The outwardly protruding element is completely encapsulated by the encapsulating compound in the encapsulating process. If a display element is present, the enclosing medium (21) must have a suitable optical transmissivity .

Fig. 6 shows a function module, e.g. of a vibrator (22), which requires a volume (23) to be kept free in the interior. The volume kept free was made possible by a housing container (24) that remains in the interior after the encapsulating process and forms a permanent formwork . Fig. 7 shows an integrally cast outer element (25), e.g. in the form of an operating element, which has been introduced with the free surface already in the electrically connected end position. The enclosing medium (27) can be both opaque and also transparent.

Fig. 8 shows a component (28) placed directly on the encapsulating compound, this embodiment requiring that the component itself is water-tight, and the electrical connection (26) to the inner components (30) must be of a pluggable configuration.

List of reference symbols

1 battery compartment

2 electronic components

3 drive/motor components

4 threaded rod/telescope component

5 ampoule compartment

6 adapter (connecting catheter/ampoule)

7 cap

8 encapsulating compound

9 user interface components

11 structural group protruding outwards with a free surface during use

12 electrical contact/connection

13 shaped body

14 signal transmitter

15 Resonance chamber

16 water-tight piezo element

17 individual contacts water-tight piezo element

20 Display element

21 Enclosing element for display medium

22 vibrator (vibra)

23 volume for vibra/vibrator

24 interior housing container

25 Integrally cast outer element

26 wired connector

27 enclosing medium (opaque/transparent)

28 component, directly placed on the encapsulating compound

30 inner components

Claims

Claims :

1. Portable medical appliance with a housing in which functional modules (1, 2, 3, 4, 5, 6, 9) of the medical appliance are received, and in which hollow spaces present between or in the functional modules are at least partially filled with a compound (8) .

2. Portable medical appliance according to Claim 1, characterized in that it is a blood glucose meter.

3. Portable medical appliance according to Claim 1, characterized in that it is a device for dosed administration of a liquid medicament, comprising: a) a seat for a container (5) that receives the liquid medicament to be administered; b) a discharge device (4) for dosed delivery of the liquid medicament from the container (5); c) a device (3) for driving the discharge device, and d) a control unit (2) for controlling the drive, with hollow spaces being present between the parts a) to d) and being at least partially filled with a compound.

4. Portable medical appliance according to Claims 1 to 3, characterized in that the compound has shock-absorbing properties.

5. Portable medical appliance according to Claims 1 to 3, characterized in that the compound has waterproofing properties.

6. Portable medical appliance according to Claims 1 to 3, characterized in that the compound has properties affording resistance to chemicals.

7. Portable medical appliance according to Claims 1 to 5, characterized in that the hardness of the compound after the curing process lies in the range of 40 - 80 Shore.

8. Portable medical appliance according to Claims 1 to 5, characterized in that the compound in the cured state has a transmissivity of greater than 80%, relative to a wavelength of light of 400 - 700 nm, at a layer thickness of 10 mm.

9. Portable medical appliance according to Claims 1 to 5, characterized in that the compound is a crosslinkable silicone compound.

10. Portable medical appliance according to Claims 1 to 5, characterized in that the compound is a vulcanizable rubber.

11. Portable medical appliance according to Claims 1 to 5, characterized in that the compound is a gel- like liquid or a viscous medium.

12. Portable medical appliance according to Claims 1 to 8, characterized in that the enclosing compound essentially forms the outer walls of the housing.

13. Portable medical appliance according to the preceding claims, characterized in that the housing interior is filled completely with the compound.

14. Portable medical appliance according to Claim 13, characterized in that an accumulator element is embedded as an energy source and can be charged by inductive, capacitive or galvanic coupling from a device external to the appliance.

15. Portable medical appliance according to Claim 14, characterized in that a galvanic connection is located in a cavity of the medical appliance.

16. Portable medical appliance according to Claims 1 to 12, characterized in that hollow spaces are formed in the encapsulating compound to permit a reduction in weight.

17. Portable medical appliance according to Claims 1 to 12, characterized in that the housing has an encapsulated compartment that receives some of the functional modules.

18. Portable medical appliance according to Claims 1 to 5, characterized in that the functional modules are connected by fluidic and/or electrical connections .

19. Portable medical appliance according to Claim 18, characterized in that the modules can be connected by plugs, and these plug connections can be encapsulated in a vacuum-tight manner.

20. Portable medical appliance according to Claims 1 to 10, characterized in that the functional modules, combined in higher-order groups, are fitted in encapsulated form into a compartment.

21. Portable medical appliance according to Claims 1 to 10, characterized in that the functional modules are held and positioned by a framework.

22. Portable medical appliance according to Claim 21, characterized in that the framework is of a rigid design and largely takes up the static forces from outside .

23. Portable medical appliance according to Claim 22, characterized in that the framework has vibration- absorbing properties.

24. Portable medical appliance according to Claims 1 to 5, characterized in that the medical appliance contains at least one means for visual, tactile and vibratory display of information.

25. Portable medical appliance according to Claim 24, characterized in that the vibratory display is connected to the outside of the housing via a solid-borne sound coupling.

26. Portable medical appliance according to Claim 25, characterized in that a resonance chamber (15) is created through the creation of hollow spaces, forming resonance bodies (14) suitable for the signal transmitters.

27. Portable medical appliance according to Claims 1 to 5, characterized in that the housing is enclosed by a removable outer housing shell (10) .

28. Portable medical appliance according to Claim 27, characterized in that the outer housing shell (10) is made of material resistant to salt water and sweat .

29. Method for producing a portable medical appliance according to Claim 1, characterized in that at least one functional element is encapsulated with the compound and then connected to the remaining functional elements.

30. Method for producing a portable medical appliance according to Claim 29, characterized in that, during the encapsulating process, the structural groups protruding outwards with a free surface are represented by one or more shaped bodies (13) which, during the encapsulating process, ensure that the space later occupied by the interfaces can be kept free .

31. Method for producing a portable medical appliance according to Claim 30, characterized in that at least one compound is applied to the functional modules by injection moulding.

32. Method for producing a portable medical appliance according to Claim 30, characterized in that the compound is composed of a thermoplastic which, by means of heating, adopts a defined shape enclosing the functional modules and then, by means of cooling, hardens.