WO2010108838A1

WO2010108838A1 - Improved electronic blister pack

Info

Publication number: WO2010108838A1
Application number: PCT/EP2010/053483
Authority: WO
Inventors: Vilhelm Lindman; Leif Henrik Eriksson
Original assignee: Cypak Ab
Priority date: 2009-03-26
Filing date: 2010-03-17
Publication date: 2010-09-30

Abstract

The invention refers to electronic blister packages where the number of cavities and/or pushbuttons of a blister container that can be monitored by an electronic module are expanded. Conductive traces (101, 102) connected to the I/O of the electronic device are used in different ways to obtain either resistance change or complete rupture of the trace depending on configuration shown later.

Description

IMPROVED ELECTRONIC BLISTER PACK DESCRIPTION

Technical field

The invention refers to the field of electronic blister packages where a printed circuit and an electronic module enable detection of removal of an object out of a cavity of the blister package.

Background of the invention

Blister containers comprising a number of cavities for storing tablets / pills and the like are sometimes provided with electronic detection systems for detecting removal of an object from a cavity. Electronic blister packages are described in for example US 6 244 462, WO

9407184, WO 2007/077224.

The electronic blister containers are used for many purposes, for example in order to survey or control user behaviour. The blister container can also be equipped with buttons forming questions for user feedback. Reminders can be implemented e.g. using embedded audio or light emitting components. Information stored in the blister container electronics can be accessed using wireless communication such as RFID.

Commonly, using this type of solution, it is also desirable not only to detect that an arbitrary blister cavity has been accessed, but also exactly which cavity has been accessed. As an example, this may be be especially important in drug regimens where the dose or type if drug is tailored for the patient and may differ between times of day as well as day-to-day.

In short, an electronic blister pack comprises typically a monitoring device, e.g. a PCB

(Printed Circuit Board) with mounted conventional electronic components and an Integrated

Circuit (IC) e.g. an ASIC. The PCB is in turn mounted onto the actual blister pack, that holds the blister with the blister compartments. Alternatively a plastic film may be used. The blister pack also contains conductive traces that are typically printed onto the paper board or the plastic film. When for example a blister is broken this event is detected by the electronics and is subsequently stored and time stamped in the electronics.

The integrated circuit has a maximum number of input/outputs, I/Os, that can be connected to the conductive traces of the blister pack. Therefore the maximum number of blister compartments or buttons (from hereon referred to as detection points) is also limited.

One way to extend the number of detection points it is to add electronic components, like multiplexers etc to the PCB. Doing so will add cost, complexity and physical size to the product. The number of I/Os is limited for several other reasons. One is the physical dimension of the

PCB, that should be kept as small as possible to fit into the blister container. Another reason is that contact points between the PCB and the printed pattern must be kept above a given size, the size determined by e.g. production inaccuracy as well as contact resistance considerations.

Therefore the number of cavities that may be monitored in a blister container is limited by geometrical factors of the blister container as well as by the available number of inputs on the electronic unit.

In some cases there is a need for a larger number of cavities. Thus there is a need for a solution that can allow for this extended number of cavities without a corresponding increase in cost, size and complexity.

Another limiting factor when one trace per cavity is used is the routing of conductive traces in the blister container. The Blister to be monitored is often strictly regulated as it can contain medicine and can often not be changed. Small blister with many cavities are very difficult to rout if one trace per cavity is needed. In such cases it is desirable to use one trace to monitor several cavities.

Description of the invention

The invention allows expanding the number of cavities and/or pushbuttons of a blister container that can be monitored by the electronic module. Conductive traces connected to the

I/O of the electronic device are used in different ways to obtain either resistance change or complete rupture of the trace depending on configuration. .

The conductive traces can be printed directly onto a substrate or be printed on a film (e.g. plastic) that is in turn attached on the substrate. The electronic module is also attached on the substrate or onto the film, respectively, and is electrically connected to the conductive traces.

This substrate is then attached to the blister or container forming a complete electronic blister container.

The conductive traces can be carbon/graphite, silver, conductive polymer or any other common conductive material. The material can be printed with preferably screen printing, offset, ink-jet, gravure or any other suitable method of deposition.

Monitoring of the trace integrity can be done by monitoring an applied voltage, current, resistance or impedance of the conductive traces using the electronic unit. We will here discuss in terms of electrical resistance, however it is obvious to anyone skilled in the art that it could equally apply to voltage, current or (complex) impedance The invention can be implemented in two electrically different ways further described in the detailed description of the invention.

By using a design in accordance with the invention, it will also be possible to fit more detection points to a given area or the same number of detection points will occupy a smaller area. This has the advantage that for example more cavities for tablets can be fitted into a package without making the package larger and without losing the ability to detect breakage of a cavity.

By using a design in accordance with the invention the number of cavities that can be monitored is at least doubled.

Consideration must be taken to the fact that printed conductive traces can have variable resistance during the lifetime of the blister container. This fact is due to variations in temperature, humidity, mechanical ware and other environmental effects on both the printed trace as well and the substrate they are printed on. This change in trace resistance must never be allowed to trigger false detection of a removed cavity.

Detailed Description of the Invention

List of figures:

Figure la-d describes the functionality of the first connection in a series example.

Figure 2 Schematic presentation of a trace.

Figure 3a-d describes the functionality of the second connection in series example.

Figure 4 a-d describes the functionality of the connection in parallel detection.

Figure 5 Schematic presentation of a trace in figure 4.

Figure 6 a-e show double reference traces

Figure 7 a-f show a connection in series with double ground detection

An example of an electronic blister pack capable of detecting a plurality of tablet removals using a reduced number of channels is shown in figure 1. The figure describes the use of parallel connection of traces where one trace is routed pass each cavity to be detected. When a cavity is removed, the overall trace resistance will increase. As the properties of parallel connected resistors give that the total resistance of two parallel resistors can never be greater the each of the two resistors, the difference in resistance should be as big as possible to maximize the total change in trace resistance. One way of obtaining this is to use a mix of carbon and silver in production or simply to use different thicknesses of the traces.

The reference numbers of figure 1 show:

101 Reference trace, connected to monitoring device.

102 Tablet sensor conductive trace, connected to monitoring device. 102a-c Conductive trace running over the tablet lids.

102d Tablet sensor conductive trace, connected to Reference trace.

103 Thin conductive trace coupled parallel to 102. Resistance of 103 is significantly higher than to 102.

103a-c Connector traces between the thin and thick conductive traces.

104 Paperboard substrate 105a-c Perforated tablet lids

In the description below, the numbers are approximate, but realistic values.

Figure Ia: Conductive traces (101) and (102) are connected to an electronic monitoring device, which measures the resistance of the traces. In ground state, the resistance will be mostly dependant on the resistance of the Reference and the thick conductive trace (101) and

(102), while the thin conductive trace (103) will leave an insignificant contribution to the overall resistance.

At any time, either of the lids, 105a-c can be removed. This is shown in figure Ib, where 105b is removed. As a result, the trace 102b is disrupted, and the signal must pass via 103c and

103b, giving an overall increment of the resistance. The following figures Ic to Id are analogous. A notable fact is that when all tablets are removed, it is still possible to conduct signals through the traces.

For each lid removed a detectable change in overall trace resistance can be detected by the electronic module.

Displayed as an electrical schematic equivalent, the traces routed in figure 1 will look like figure 2.

The reference numbers of figure 2 show:

201 Reference trace, connected to monitoring device.

202 Tablet sensor conductive trace, connected to monitoring device (the sum of 102 and 102d).

202a-c Conductive traces running over the tablet lids.

202d Connection trace to first tablet lid from reference trace

203 a-c Conductive traces parallel to the traces over the tablet lids, 202.

Before any tablet is removed the overall trace resistance, called ground state, will be 23kOhm with given values. Values are estimates of real case implementations using carbon ink. For each of the lids removed the corresponding trace resistance 202a, 202b and 202c will become infinite and the only 203 a, 203b and 203 c will conduct. Each removal will give and increase in overall trace resistance given in the table below. Original state: 23kOhm

1^st removal: 32kOhm

2^nd removal: 41kθhm

3^rd removal: 50kOhm

Table 1 : Resulting overall trace resistance increase per lid removed.

Using different means of sensing the trace resistance or impedance (if necessary in combination with algorithms) it is possible to sort out changes to the overall trace resistance due to tablet removal from normal variations due to environmental impact such temperature changes. However, it will not be possible to detect which one of the tablets that has been removed.

Another way to implement this is shown in figure 3 a-d, where one broad trace 302d, runs over the tablet lids. When a tablet is pressed out only a small part of conductive ink remain around the opening (or only on one side).

The reference numbers in fig 3 show:

301 Reference trace, connected to monitoring device.

302 Tablet sensor conductive trace, connected to monitoring device. 302a-c Conductive trace running over the tablet lids.

302d Tablet sensor conductive trace, connected to Reference trace.

303a-c Connector traces between the thin and thick conductive traces.

304a-c Perforated tablet lids

In figure 3 a conductive traces (1) and (2) are connected to an electronic monitoring device, which measures the resistance of the traces. The resistance of 302 (a-d) will be low, since the impact of the thin perforation lid bridges are insignificant. At any time, either of the lids,

305a-c can be removed. This is shown in figure 3b, where 305b is removed. As a result, the trace 302b is disrupted, and the signal must pass via the thin 303b, giving an overall increment of the resistance. The following figures 3c to 3d are analogous. A notable fact is that when all tablets are removed, it is still possible to conduct signals through the traces.

For each lid removed a detectable change in overall trace resistance can be detected.

An example of an electronic blister pack capable of detecting a plurality of tablet removals using a reduced number of channels is shown in figure 4.

The reference numbers in fig 4 a-d show:

401 Reference

402 Tablet sensor conductive trace, split into three parallel traces 402a-c. 402a-c Thin conductive traces running over the tablet lids. These traces should have significantly higher resistance compared to the rest of the system. 402d Tablet sensor conductive trace, connected to Reference trace

404 Paperboard substrate

405 a-c Perforated tablet lids

In the description below the number are approximate, but realistic values.

Fig 4a: Coupling scheme: The reference, 401, is connected to conductive trace 402 via three parallel traces, 402a-c, that run over tablet lids. The reference and the conductive traces 401 and 402 are connected to an electronic monitoring device, which measures the resistance of the traces. In ground state, the resistance will be evenly dependant on the reference 401 and trace 402a-d. At any time, either of the lids 405a-c can be removed, changing the resistance of the overall system. It will be possible to tell that a lid has been removed, but not which lid.

When all tablet lids have been removed, the circuit will be open.

As an electrical equivalent scheme, the trace will look like fig 5. This scheme holds a threefold splitting of the trace, resembling the three tablet lids. The result of a simulation with the numbers in the figure gives the following values.

Ground state: 30kOhm

1^st removal: 35kOhm

2^nd removal: 50kOhm

3^rd removal: infinite

Using different means of sensing the trace resistance (if necessary in combination with algorithms) it is possible to sort out increments in the resistance due to tablet removal from normal variations due to environmental impact such temperature changes. However, it will not be possible to detect which one of the tablets that has been removed.

Another way to detect multiple tablet removals using a reduced number of channels is to use two separate reference traces, as can be seen in fig. 6 a-e. In this case it is open/close detection rather than a quantitative change in the trace resistance that is detected. The sensing means is therefore easier to implement and variations in trace resistance due to environmental changes, such as heat and moisture, and printing process variations have less impact.

By using the possibility to set an I/O of the ASIC on the electronic module in high impedance mode, e.g. three state mode, one of the reference traces can be considered to be un connected.

The reference numbers in fig 6a-e show:

601 Reference trace no 1

602 Reference trace no 2 603 Sensor trace, split for double cavity detection in 603a

604 Sensor trace, split for double cavity detection in 604a

605 Sensor trace, split for double cavity detection in 605a

606 Sensor trace, split for double cavity detection in 606a

607 607a tablet cavity connected to reference no 1, 607b tablet cavity connected to reference no 2

608 608a tablet cavity connected to reference no 1, 608b tablet cavity connected to reference no 2

609 609a tablet cavity connected to reference no 1, 609b tablet cavity connected to reference no 2

610 610a tablet cavity connected to reference no 1, 610b tablet cavity connected to reference no 2

611 Paperboard substrate

The following scenario is shown in figures 6 a-e:

Fig. 6a: Schematic double reference detection method in ground state. No tablets have been removed.

Fig. 6b: Tablet 10b has been removed.

Fig. 6c: Tablet 9b has been removed.

Fig. 6d: Tablet 10a has been removed.

Fig. 6e: All tablets have been removed.

To detect a tablet removal, the monitoring module will scan the inputs 603-606 while alternating between references 1, 601, and 2, 602. Alternating between the references, 601 and 602, means setting one of the traces in high impedance mode while using the other as reference during one measuring cycle and alternating the start during the following measuring cycle.

In figure 6b tablet (610b) is removed. To detect this reference trace 1, 601, is in high impedance mode while reference trace 2, 602, is used as reference. Measuring on sensor trace

606 connected to both 610a and 610b through 606a will indicate an open trace in 610b as

610a is connected to a high impedance trace. If reference trace no 1, 601, is used as reference a closed loop will be formed through 601, 610a, 606a and 606 thus giving no tablet has been removed. Hence by altering the reference between reference trace no 1, 601, and reference trace no 2, 602, it will be possible not only to monitor a plurality of events for each tablet sensor trace, it will also be possible to detect exactly which tablet has been removed.

Reference level It is possible to use any level of the reference as long as they are not connected simultaneously. If both have the same level and are connected at the same time, it is analogue to fig 4 as the tablets are connected in parallel.

Figure 7 a-f show connections in series with double ground detection.

The reference numbers in figures 7 a-f show:

701 Reference no 1

702 Reference no 2

702d Tablet sensor conductive trace, connected to Reference trace

703a-f Thin conductive traces running parallel to 704. The resistance of 703a-f are significantly larger than 704.

704 Conductive trace, tablet sensor that run over the tablet lids. The resistance of 704 is significantly lower than 703a-f.

705 a-f Perforated tablet lids

706 Tablet sensor conductive trace, split into the parallel traces 703 and 704.

707 Paperboard substrate

Figure 7 a-f show the following scenario: a: Ground state, no tablet removed b: Tablet no 705 d removed c: Tablet no 705 e removed d: Tablet no 705b removed e: Tablet no 705 c removed f: All tablets removed

The configuration in fig 7 includes two references and only one tablet sensor trace.

It will be possible to measure that a tablet has been removed and to which reference the tablet is connected, but it will not be possible to tell which tablet has been removed.

Conductive traces 701, 702, and 706 are connected to the electronic monitoring device.

In fig 7b tablet 705d is removed. This is recorded by the monitoring device as an increment in resistance measured in 706 with reference to 702. In fig 7c tablet 705 e is removed and consequently an analogous increment is recorded. In fig 7d tablet 705b is removed and the following increment in resistance will be monitored at 706 with reference to 701.

The number of blister compartments per I/O channel that can be surveyed by a monitoring device can vary. Depending on printing technique and material up to around 10 cavities per channel for screen-printed packages and even more for inkjet printed packages can be possible. For the combination carbon ink and screen print the number may be slightly lower.

Claims

1. An electronic blister pack designed for detection of removal of an object from a cavity of the blister packaging, comprising a base with a plurality of cavities, a covering sheet covering the plurality of blister compartments and a printed circuitry connected to a monitoring device via I/O ports, the monitoring device being capable of recording changes in resistance or impedance of a current flowing through the printed circuitry, characterised by that at least one I/O port is connected to more than one cavity detection point via printed conductive sensor traces.

2. An electronic blister pack according to claim 1, characterised by that the printed circuitry comprises a conductive reference trace, a cavity sensor trace and a resistance trace having significantly higher resistance than the sensor trace.

3. An electronic blister pack according to claim 1 and 2, characterised by that the printed circuitry connected to an I/O port of the monitoring device comprises a reference trace connected to the I/O port, a cavity sensor trace connected to the I/O port and to the reference trace and said cavity sensor trace having serially connected parts, where each part is crossing a cavity and a resistance conductive trace, having higher resistance than the sensor trace and coupled in parallel to the sensor trace and said resistance conductive trace having parts connected to the parts of the cavity sensor trace, so that a breakage of a cavity will result in that the current flowing through the resistance conductive trace and the monitoring device recording a higher resistance for the printed circuitry for each breakage of a blister compartment.

4. An electronic blister pack according to claim 1, characterised by that that the printed circuitry connected to an I/O port of the monitoring device comprises a reference trace and a cavity sensor trace serially connected to the reference trace and the I/O port and where said cavity sensor trace has a width over the blister compartments that is broader than the cavity width, so that a conductive string of the cavity sensor trace remains after breakage of the cavity and the monitoring device can record a higher resistance for the printed circuitry for each breakage of a cavity.

5. An electronic blister pack according to claim 1 and 2, characterised by that the electronic circuitry comprises more than one reference trace and a cavity sensor trace crossing more than one cavity coupled to each reference trace, the monitoring device will switch between reference traces and thereby individual cavities where the blister has been broken can be detected.