Timing device

Abstract

The timing device is a lifetime monitor for indicating when the usable lifetime of a product has ended or for indicating the timing for regular usage of a product. The timing device has a timing initiator, a power supply in the form of a membrane zinc air battery and a visual or audible indicator. The timing initiator is a tear-off air blocking membrane which lets in air when the tear off film is removed. The timing device is capable of indicating a predetermined passage of time which is substantially independent of ambient temperature.

Claims

1. A timing device comprising a timer, an informative device, and a trigger and wherein the timing device is adapted for attachment to a product container; the trigger is connected to the timer and adapted to automatically activate the timer the first time the product container is opened; and the timer is connected to the informative device which is configured to confirm expiration of a predetermined duration of time since the product container has been opened representative of the end of useful life of the product, and wherein the timer is a flexible zinc air battery, the flexible zinc air battery containing a selected amount of components which are exhausted at the end of the predetermined duration of time.

2. A timing device as claimed in claim 1, wherein the timing device is a multi-laminar product.

3. A timing device as claimed in claim 1, wherein the timer is substantially independent of ambient temperature.

4. The timing device of claim 1, wherein the trigger comprises an adhesive tab adapted to overlie and be attached to the opening junction of the product container.

5. The timing device of claim 1, wherein the trigger is attached to an air valve.

6. The timing device of claim 1, wherein the informative device includes a display which has a permanent visual message that is obscured until elapse of the predetermined duration of time.

7. The timing device of claim 1, wherein the informative device includes a display for displaying a visual message generated after expiration of the predetermined duration of time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

(2) FIG. 1 illustrates schematically a laminar membrane structure for a first embodiment of a lifetime monitor in accordance with the present invention;

(3) FIG. 2 illustrates a multi-layered structure of a membrane zinc-air laminar battery for use with the life time monitor of FIG. 1; and

(4) FIG. 3 illustrates schematically an electroluminescent film structure in an alternative embodiment of the lifetime monitor of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) A timing device in the form of a lifetime monitor 10 is shown in FIG. 1. The monitor 10 generally comprises a main body 11 including a timer and a tab 12. The lifetime monitor 10 is initiated by the opening of the product container to which it is attached. This trigger mechanism is preferably implemented by means of the adherent tab 12 which is consumer friendly and can precede an unscrewing action if appropriate. The action of removing the tab 12 can remove a light blocking foil, remove a conducting strip, allow access of air as in a zinc air battery or be some other mechanism for auto-initiating the timer. Zinc air batteries can also act as the timing mechanism, having an output voltage which becomes zero when the zinc is depleted. The tab 12 may also be in the form of a perforated strip which is torn in the act of unscrewing the lid of a container to which it is attached.

(6) The main body 11 of the monitor functions as the timer and indicator mechanism. Thus, the main body may include at least three membrane layers stacked one on top of the other in a laminated structure. The first membrane is at a first surface of the main body 11. The first membrane which is porous is coated with an adhesive material and is impregnated with a first compound e.g. an acid. The first membrane is separated from the third membrane by a diffusion membrane and the third membrane includes a second compound that is reactive with the first compound. As the first compound diffuses through to the third membrane it reacts with the second compound so that the concentration of the first compound is reduced to zero after a time related to the concentration of the second compound in the third membrane.

(7) The third membrane acts as an indicator membrane impregnated with the second compound. The first and second compounds are chosen so that when they react this produces a visual change, e.g. alkali and litmus dyes (Roccella tinctoria), i.e. constant pH buffer in the alkali range is maintained until the alkali is depleted.

(8) With the monitor 10 shown in FIG. 1, the colour of e.g. a message printed in the alkali region i.e. the third membrane would change from blue to red and could be made to stand out from a blue, unchanged, background. Many compounds for which titration is possible would be suitable for use in this way, including acid/alkali, oxidation/reduction processes etc.

(9) FIG. 2 illustrates an alternative timing mechanism for use with the lifetime monitor 10. In FIG. 2 the main body 11 of the monitor includes a flexible and conformable laminar battery of the type known to have been used in Polaroid camera film packs. The laminar battery is used in combination with a light emitting material which will continue to give off light for as long as the battery delivers charge. Any of the existing battery concepts could be used for delivering the necessary charge to the light emitting material. Where a laminar battery is required, those described in U.S. Pat. Nos. 4,092,464, 4,007,472 and 4,098,965 may be used. However, preferably an adaptation of known laminar battery technology is used to provide a laminar and flexible zinc/air battery. from Alternative laminar power cells are copper/zinc and lithium ion etc cells. Suitable light emitting or indicator materials include organic light emitting diode sheets (OLEDs), leds, LCDs and electronic paper.

(10) For the lifetime monitor the preferred battery is a zinc air laminar battery that is flexible and conformable. The component(s) of the battery and the amount of the component(s) are selected so that the component(s) are depleted as the battery is discharged. In this way the duration of the battery life may be controlled. The lifetime of the battery is therefore selected to correspond to the product lifetime.

(11) In a further alternative, the timing mechanism may comprise a silicon or organic timing circuit printed or put down by other means on a polymer or graphene membrane, powered by a laminar battery or by a photons to electrons converter. The indicator material described above would be used to show when the product lifetime had expired.

(12) In a yet further alternative timing mechanism (not illustrated), a laminated structure includes an oxidisable or reactive film which is exposed to air when the trigger tab 12 is removed to open the container. When the film is totally reacted, the end of life message is revealed.

(13) Where the surface of the product container includes microstructures, channels may be incorporated in the container mould to allow the possibility of other diffusion processes such as gas diffusion to be used in combination with the lifetime monitor.

(14) All of the timing mechanisms described above are preferably independent of those temperature effects which would affect the timing. However, it is also envisaged that the lifetime monitor 10 may be automatically responsive to temperature limit(s) to allow for shortening of the product lifetime where the product is exposed to temperatures above the manufacturers' recommended storage temperature e.g. 5-25 C.

(15) A change of colour, either per se, or to differentiate a message from the surrounding area is an acceptable means of indication as a customer information display. Where the timer involves charge or voltage changes, a simple black and white LCD or electronic paper consumes little power to deliver the message. This minimises the size and charge delivery capability required of the battery. Where possible, colour change is preferred and can be realised by using OLED screen material.

Examples

(16) Colour Change

(17) FIG. 1 is a representation of a multiple membrane structure wherein the tabbed upper membrane 13, is transparent and is coated with liposomes containing a weak acid, e.g. acetic acid and which is impervious to the contents of the membrane below. Membrane 14 is transparent and is micro- or nano-structured to cause the liberated acetic acid to reach membrane 15. Membrane 15 is structured such as to allow the diffusion of the acid to membrane 16 which is impregnated with a pH sensitive indicator dye such as litmus and a measured quantity of an alkali such as calcium hydroxide in solution.

(18) Electrical Display Type

(19) FIGS. 2 and 3 illustrate a timing device including a zinc air laminar battery to power a display (not illustrated) to indicate residual life of a product. FIG. 2 shows the multi-layered structure of the membrane zinc-air battery: a tear off air blocking membrane 20; a porous air input controlling layer, which lets in air when the tear off film is removed 21; a porous air electrode, the anode 22; an interface containing electrolyte 23; a zinc electrode 24; an outer adhesive film which attaches the battery to the package 25.

(20) The interface containing electrolyte 23 is preferably formed of a woven material having a hole diameter of 1-50 microns, more preferably 1-10 microns, more preferably still 2-5 microns and ideally 2 microns. The woven material may be made from man-made materials such as polyester, polypropylene, nylon or other plastics or from natural materials such as silk. Plastock 1-10 micron mesh is an example of a suitable material for use as the interface containing electrolyte.

(21) A membrane zinc air battery is a flexible laminar battery making it particularly suitable for use as part of an adhesive label particularly for curved packaging surfaces because the laminar zinc air battery is capable of conforming to the curvature of a surface to which it is applied.

(22) FIG. 3 shows a multilayer structure of an electroluminescent membrane for use in the lifetime monitor. A layer of organic phosphor with coloured overlays is sandwiched between two conductors and electric current applied across the phosphor layer rapidly charges phosphor crystals which emit visible light. The film thickness is typically between 0.25 mm-0.5 mm. The electroluminescent media is typically constructed using the following five layers: a clear graphics layer at the top 30; a clear conductive layer 31; a phosphor layer 32; a dark conductive layer 33; a insulating layer at the rear 34.

(23) The use of an organic phosphor requires laminar electronics circuitry to convert a zinc air laminar battery voltage of about 1.5 volts to the 36 volts square wave needed by the fluorescent display. An alternative display which can operate directly from 1.5 volts is the OLED (Organic Light Emitting Diode) display, which is available and manufactured by several companies, e.g. Sony. OLEDs have quite simple structures: a luminescent organic thin film is sandwiched between cathode and anode. Charge carriers, such as electrons and holes, are injected into the organic layer, where they meet to form excitons. When the excitons decay, the organic molecules emit their characteristic light.

(24) Sony's recent flexible and transparent organic light emitting diode (OLED) technology is currently being shown in prototypes featuring an OLED a mere 0.2 mm thick. The prototype devices are a Vaio notebook, a flexible e-book, and a Walkman bracelet. The OLED screen is transparent and flexible, and the viewing angle range is almost unlimited. OLED technology has a number of advantages over LEDs, including higher efficiency, faster response times, and no requirement for backlighting. The devices also have very low energy needs.

(25) It will be apparent that the components of both timing mechanism and indicator mechanism may be deposited on the same films and interconnected by transparent deposited conductors.

(26) Furthermore, the resulting flexible composite film can be wrapped round tubes or other curved product container surfaces as well as any symmetrical or flat packaging to emit light for message display, or to screen an expiry message until available power has run out when the expiry message is revealed. In the case of a zinc air laminar battery the lifetime is defined by the quantity of zinc and by the rate of air (i.e. oxygen) input to the battery e.g. by making the pore size of the air diffusion layer change appropriately as a function of temperature and as such can be made to be independent of the ambient temperature to which the package is exposed. An additional virtue of this approach is the ability to tailor the display to improve the visual appearance of the package.

(27) The timing device may be provided as a sheet of peel-off lifetime labels each label having an adhesive rear surface. The lifetime labels may be removed individually from their releasable backing material and adhesively attached to items including, but not limited to, non-food stuffs, the packaging of perishable foods stuffs and/or frozen food to indicate to the consumer a date in the future beyond which the item should not be used.

(28) A further use of the timing device is in secondary packaging as part of the management of a supply chain. The timing device may be used to indicate which pallets of products have been in a warehouse for the longest and so should be sent to retailers first.

(29) A still further use of the timing device is in the generation of a visual or audible reminder at regular time intervals for the repeated use of a product. Thus, the timing device may be used in association with the packaging of products such as toothpaste or medicaments to generate a visual or audible reminder once or twice a day to encourage regular use. With this alternative use of the timing device, a power supply in the form of a laminar zinc air battery is preferred connected to a solid-state counter or other timing mechanism to trigger at regular time intervals the generation of a visual or audible reminder.

(30) Further changes and alterations to the embodiments described herein are envisaged with departing from the scope of the invention as defined in the appended claims.