The present invention relates, in general, to electronic devices and, in particular, to electronic device casings that include electrical contacts and associated methods.
The determination (e.g., detection and/or concentration measurement) of an analyte in, or a characteristic of, a fluid sample is of particular interest in the medical field. For example, it can be desirable to determine glucose, ketone bodies, cholesterol, lipoproteins, triglycerides, acetaminophen, hematocrit and/or HbA1c concentrations in a sample of a bodily fluid such as urine, blood, plasma or interstitial fluid. Such determinations can be achieved using a hand-held test meter and associated analytical test strips that employ, for example, visual, photometric or electrochemical determination techniques. Such hand-held test meters, as well as a variety of other electronic devices, are typically configured to hold and connect with batteries (e.g., coin cell batteries) that are employed as the device's power supply and/or to electrically connect with a variety of associated items such as, for example, analytical test strips.
In a first aspect of the invention, there is provided a watertight casing for an electronic device, the watertight casing comprising: an electrically-insulating plastic case with: an inwardly facing surface; and an outwardly facing surface; at least one electrically-conductive thermoplastic elastomer (ECTPE) contact that includes: a proximal contact portion with a proximal contact surface; a distal contact portion with a distal contact surface, and a channel portion connecting the proximal contact portion and the distal contact portion, wherein the at least one ECTPE contact is integrated with the electrically-insulating plastic case such that the ECTPE contact extends through the electrically-insulating plastic case from the outwardly facing surface to the inwardly facing surface; and wherein the proximal contact surface is disposed in proximity to the inwardly facing surface and the distal contact surface is disposed in proximity to the outwardly facing surface; and wherein the at least one ECTPE contact is adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface and the inwardly facing surface is present therebetween.
The electrically-insulating plastic case may be configured as at least a portion of a hand-held test meter for the determination of an analyte in a bodily fluid sample.
The electrically-insulating plastic case may be configured as a strip port connector of the hand-held test meter.
The at least one ECTPE contact may be configured to contact an electrochemical-based analytical test strip inserted into the strip port connector and a printed circuit board within the hand-held test meter.
The electrically-insulating plastic case may be configured as a battery compartment of the hand-held test meter.
The plurality of ECTPE contacts may be configured to contact a battery inserted into the battery compartment and a printed circuit board within the hand-held test meter.
The at least one ECTPE contact may be formed of an ECTPE material that includes a non-conductive polymer randomly doped with a conductive particle.
The conductive particle may be a carbon black particle.
The at least one ECTPE material may be elastically deformable.
The proximal contact portion may have a raised profile with respect to the inwardly facing surface and the distal contact portion may have a raised profile with respect to the outwardly facing surface.
At least the proximal contact portion and the distal contact portion may be elastically deformable.
In a second aspect of the invention there is provided a method for handling an electronic device, the method comprising: handling an electronic device that includes a watertight casing with: an electrically-insulating plastic case; and at least one electrically-conductive thermoplastic elastomer (ECTPE) contact, such that an outwardly facing surface of the watertight casing and a distal contact portion of the ECTPE contact in proximity to the outwardly facing surface are subjected to moisture, and preventing the moisture from reaching an inwardly facing surface of the electrically-insulating plastic case and a proximal surface of the ECTPE contact in proximity thereto in a passive manner due to the ECTPE contact being integrated with the electrically-insulating plastic case such that the ECTPE contact extends through the electrically-insulating plastic case from the outwardly facing surface to the inwardly facing surface with the ECTPE contact being adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface and the inwardly facing surface is present therebetween.
The handling may also be such that the outwardly facing surface of the watertight casing and a distal contact portion of the ECTPE contact in proximity to the outwardly facing surface are subjected to dust, and the preventing may also be such that the dust is prevented from reaching an inwardly facing surface of the watertight casing and a proximal surface of the ECTPE contact in proximity thereto in a passive manner due to the ECTPE contact being integrated with the electrically-insulating plastic case.
The electrically-insulating plastic case may be configured as at least a portion of a hand-held test meter for the determination of an analyte in a bodily fluid sample.
The electrically-insulating plastic case may be configured as a strip port connector of the hand-held test meter.
The at least one ECTPE contact may be configured to contact an electrochemical-based analytical test strip inserted into the strip port connector and a printed circuit board within the hand-held test meter.
The electrically-insulating plastic case may be configured as a battery compartment of the hand-held test meter.
The plurality of ECTPE contacts may be configured to contact a battery inserted into the battery compartment and a printed circuit board within the hand-held test meter.
The at least one ECTPE contact may be formed of an ECTPE material that includes a non-conductive polymer randomly doped with a conductive particle.
The conductive particle may be a carbon black particle.
The at least one ECTPE material may be elastically deformable.
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention, in which:
The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict exemplary embodiments for the purpose of explanation only and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.
In general, watertight casings (e.g., a battery compartment casing or a strip port connector casing) for an electronic device (for example, a hand-held test meter) according to embodiments of the present invention include an electrically-insulating plastic case and at least one electrically-conductive thermoplastic elastomer (ECTPE) contact. The electrically-insulating plastic case includes inwardly and outwardly facing surfaces. The ECTPE contact that includes a proximal contact portion with a proximal contact surface, a distal contact portion with a distal contact surface, and a channel portion connecting the proximal contact portion and the distal contact portion. In addition, the ECTPE contact(s) is integrated with the electrically-insulating plastic case such that the ECTPE contact(s) extends through the electrically-insulating plastic case from the outwardly facing surface to the inwardly facing surface and such that the proximal contact surface is disposed in proximity to the inwardly facing surface and the distal contact surface is disposed in proximity to the outwardly facing surface. Moreover, the ECTPE contact(s) is adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface and the inwardly facing surface is present therebetween.
As used herein, the terms “case” and “casing” refer to an outer covering or housing and the term “watertight” indicates that the described item is of such tight construction or fit as to be impermeable to water, other liquids and dust. The term “adhered” refers to any of, or a combination of, chemical bonding, inter-diffusion and mechanical interlocking. Adherence between the ECTPE contacts and the electrically-insulating plastic case can be achieved by, for example, forming the ECTPE contacts and electrically-insulating plastic case using co-injection molding (also referred to as two shot molding).
Watertight casings according to embodiments of according to embodiments of the present invention are beneficial in that, for example, they prevent water and dust from passing through the casing, along any interface between the electrical contacts and the electrically-insulating case, and entering the interior of the casing where the water and/or dust is at risk of harming electronics. Moreover, the watertight casings according to embodiments of the present invention are relatively low-cost, simple to manufacture and to easily connected to other components of the electronic device (such as a printed circuit board (PCB)) using solder-less techniques. Moreover, the outwardly facing surface of watertight casings according to the embodiments of the present invention can be beneficially cleaned with water or other suitable liquids without the risk of such water or other liquids inadvertently leaking to the inwardly facing surface and thereafter contaminating electronics or other electronic device components on the inwardly facing side of the watertight casing (i.e., on the inside of the electronic device).
Referring to
Each of these ECTPE contacts includes a proximal contact portion (110a, 110b and 110c, respectively) with a proximal contact surface (112a, 112b, and 112c, respectively), a distal contact portion (114a, 114b, and 114c, respectively) with a distal contact surface (118a, 118b, and 118c, respectively), and a channel portion (120a, 122b, and 122c, respectively) connecting the proximal contact portion and the distal contact portion of each ECTPE contact.
As is evident from
Each of the ECTPE contacts (108a, 108b and 108c) is adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface 106 and the inwardly facing surface 104 is present therebetween. Such a watertight seal is present at the interface of the ECTPE contacts and the electrically-insulating case and is a result of forming the watertight casing using, for example, a co-injection technique.
Operable electrical contact between the ECTPE contacts (108a, 108b and 108c) and solder pads of the PCB is securely established by elastic deformation of the ECTPE being pressed against solder pads of the SPC. The ETCPE contacts are pressed against the PCB by the predetermined configuration of the electrically-insulating case. Watertight case 100 can be mounted onto the PCB using any suitable technique including, for example, heat staking, surface mount technology or some other mechanically sound method of fixation.
ECTPE contacts 108a, 108b and 108c can be formed of any suitable ECTPE material. Suitable ECTPE materials include a durable thermoplastic rubber doped with electrically conductive micro-particles or electrically-conductive nano-particles. The effect of randomly doping a non-conductive polymer with an electrically conductive particle, such as carbon black, is such that once the volume fraction of the electrically conductive particle reaches a critical value, Φc, the resistivity of the composite material falls rapidly.
The equation below describes the electrical conductivity of a random dispersion polymer composite, ρ, for different values of:
ρ=ρ0(Φ−Φc)−β
This equation illustrates that the conductivity of the ECTPE material can be predetermined based on the electrically conductive particle geometry (size and shape), particle conductivity and particle volume fraction. Suitable electrically conductive particles for inclusion in an ECTPE material include, but are not limited to, carbon particles, carbon nanotubes, silver coated microspheres, nickel coated graphite, and metallic particles.
ECTPE materials employed in embodiments of the present invention can be any suitable ECTPE material including, as a non-limiting example, an ECTPE material commercially available from Premix as “Preseal TPE.” To create a watertight seal between the ECTPE contacts and the electrically-insulating plastic case, the ECTPE should have characteristics that provide for watertight seal to be formed upon such co-injection. Once apprised of the present disclosure, suitable adherence can be determined by one skilled in the art via routine experimentation.
Electrically-insulating plastic casing 102 can be formed of any suitable plastic material including, for example, polypropylene, polystyrene and polycarbonate, poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), a glass-reinforced liquid crystal polymer (LCP) and combinations thereof. The plastic material of the electrically-insulating casing is selected such that it is compatible with, for example has operable adhesion with, the ECTPE material.
Referring to
The ECTPE contacts of watertight casing 200 are identical to those of watertight casing 100. However, electrically-insulating plastic case 202 is configured, along with gasket 209, to operably attach to, and be detached from, associated plastic case MC. Therefore, watertight casing 200 can be considered a strip port connector (SPC) sub-assembly or SPC component of a hand-held test meter. Such a test meter would employ the associated plastic case MC and PCB of
Gasket 209 can be formed of any suitable material including suitable natural rubbers and suitable thermo-elastic materials. Moreover, gasket 209 is configured to provide a watertight seal between electrically-insulating plastic case 202 and associated hand-held meter case MC (also referred to as a housing), thereby providing a fully watertight housing for a hand-held test meter once watertight casing 200 and associated meter case MC are connected.
Referring to
Each of these ECTPE contacts includes a proximal contact portion (310a, 310b and 310c, respectively) with a proximal contact surface (312a, 312b, and 312c, respectively), a distal contact portion (314a, 314b, and 314c, respectively) with a distal contact surface (318a, 318b, and 318c, respectively), and a channel portion (320a, 320b, and 320c, respectively) connecting the proximal contact portion and the distal contact portion of each ECTPE contact.
As is evident from
Each of the ECTPE contacts (308a, 308b and 308c) is adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface 306 and the inwardly facing surface 304 is present therebetween.
Referring to
Once apprised of the present disclosure, one skilled in the art will recognize that watertight casing 100, watertight casing 200 and watertight casing 300 are configured to operate as a Strip Port Connector (SPC) for an associated hand-held test meter for the determination of an analyte (such as glucose) in a bodily fluid sample (e.g., a whole blood sample) using a test strip (for example, an electrochemical-based analytical test strip).
Referring to
Each of these ECTPE contacts includes a proximal contact portion (410a and 410b, respectively) with a proximal contact surface (412a and 412b, respectively), a distal contact portion (414a and 414b, respectively) with a distal contact surface (418a and 418b, respectively), and a channel portion (420a and 420b, respectively) connecting the proximal contact portion and the distal contact portion of each ECTPE contact (see
As is evident from
Each of the ECTPE contacts (408a and 408b) is adhered to the electrically-insulating plastic case such that a watertight seal between the outwardly facing surface 406 and the inwardly facing surface 404 is present therebetween.
Watertight casing 400 is configured as the upper half of a housing for a hand-held test meter and is of a predetermined geometry for accepting a battery (see
The elastic nature of the ECTPE contacts is such that the ECTPE contacts elastically deform as the battery is inserted. The ECTPE contacts are of suitable dimensions to apply an appropriate contact force to the battery terminals ensuring good electrical connection.
Simply assembling the hand-held test meter results in the ECTPE contacts making electrical connection with the PCB without the need for soldering. The electrical connection between the ECTPE contacts and the PCB is facilitated by deformation of the ECTPE contacts by, for example, a 50% deformation of the portion of the ECTPE contact that is raised above the inwardly facing surface. Such deformation is not depicted in the simplified FIGs. but would be recognized by one skilled in the art once apprised of the present disclosure. A suitable, but non-limiting, contact resistance between solder pads on the PCB and the ECTPE contacts is approximately 0.1 ohms. However, it is noted that in embodiments of the present invention, the ECTPE contacts need only be deformed by an amount that is adequate to provide an operable contact area, a secure contact, and a suitable contact resistance. The contact and between the ECTPE contacts and a PCB is the result of an applied force that results from the fixing of the watertight casing to the PCB. Such a fixing can be achieved using any suitable mechanical fixing technique such as heat staking or affixing with screws or other fasteners known to one skilled in the art.
The handling of step 510 is such that an outwardly facing surface of the watertight casing and a distal contact portion of the ECTPE contact in proximity to the outwardly facing surface are subjected to moisture and/or liquid (for example water, a bodily fluid sample or a suitable cleaning solution). In this regard, an outwardly facing surface that is subjected to liquid is also considered to have been subjected to moisture. Moreover, the term “watertight” as applied to the casing can also include, depending on the degree of adherence between the ECTPE and plastic case, casings that are not only watertight but also airtight.
At step 520 of method 500, the moisture is passively prevented from reaching an inwardly facing surface of the electrically-insulating plastic case and a proximal surface of the ECTPE contact in proximity thereto due to the ECTPE contact being integrated with the electrically-insulating plastic case such that the ECTPE contact extends through the electrically-insulating plastic case from the outwardly facing surface to the inwardly facing surface with the ECTPE contact being adhered to the electrically-insulating plastic case. Moreover, the adherence is such that a watertight seal between the outwardly facing surface and the inwardly facing surface is present therebetween.
If desired, method 500 can be modified to provide for the handling to be such that the outwardly facing surface of the watertight casing and a distal contact portion of the ECTPE contact in proximity to the outwardly facing surface are also subjected to dust, and also so that the preventing is also such that the dust is prevented from reaching an inwardly facing surface of the watertight casing and a proximal surface of the ECTPE contact in proximity thereto in a passive manner due to the ECTPE contact being integrated with the electrically-insulating plastic case.
Once apprised of the present disclosure, one skilled in the art will recognize that method 500 can be readily modified to incorporate any of the techniques, benefits, features and characteristics of water tight casings with integrated electrical contacts according to embodiments of the present invention and described herein.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that devices and methods within the scope of these claims and their equivalents be covered thereby.
Number | Date | Country | Kind |
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1314400.1 | Aug 2013 | GB | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2014/067185 | 8/11/2014 | WO | 00 |