Printed electronics, tattoos and artificial skin

I came across a recent patent application from Nokia describing a haptic communication method in which labels or tattoos on the skin can be made to vibrate when triggered by a magnetic field.  In one example the magnetic field could be initiated by a mobile phone and the user could be alerted to incoming phone calls via the sensations induced on the users skin.

The patent application was published on 15th March 2012 as US20120062371

What is claimed is:
1. An apparatus comprising:
a material attachable to skin, the material capable of detecting a magnetic field and transferring a perceivable stimulus to the skin, wherein the perceivable stimulus relates to the magnetic field.
2. An apparatus according to claim 1, wherein the material comprises at least one of a visible image, invisible image, invisible tattoo, visible tattoo, visible marking, invisible marking, visible marker, visible sign, invisible sign, visible label, invisible label, visible symbol, invisible symbol, visible badge and invisible badge.
3. An apparatus according to claim 1, wherein the perceivable stimulus comprises vibration.

Several other claims go on to describe the material in more detail and indicate that it could comprise a ferromagnetic powder.

At about the same time The University of Cambridge were publishing in the Advanced Materials journal ( Vol 24, No. 12 pp. 1558-1565) an article on the progress made by researchers in the Cavendish Laboratory towards better flexible printed electronics materials.  The work was recently highlighted in the Research Features page and applications mentioned include artificial skin and interactive playing cards.  Many of these applications are a long way off yet but the groundwork to make them possible is progressing at a rapid rate.  The new circuits developed by Drs Kronemeijer and Gili exhibited the fastest operation published to date (a few hundred KHz) using a new class of ambipolar organic materials and reduced the power supply requirements by approximately one order of magnitude so that they can already be operated using a standard 9V battery.

If anyone would like to know more about the patent applications that are emerging in this highly competitive field then please contact me at IPScope (phil.coldrick@ipscope.co.uk).

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Thin Printable Battery Patent

Most electronic circuits will require power to operate and for printed electronics devices to become a commercial success there is a need for a simple printed power supply that will last for the typical lifetime of the product.  Printed greeting cards with electronic add-ons are a classic example where the power is needed for a fairly short period of time but these are often powered by thin button cells which are not part of the printing process.  Several manufacturers are now providing printable power supplies and I have been keeping an eye on these developments.

Blue Spark Technologies recently announced an expansion of their manufacturing facilities for flexible carbon zinc batteries to meet the growing demand for printed electronics in commercial and industrial packaging.  The full article is here.  Back in October 2011 Blue Spark were granted a patent (US8029927) which covers the technology used in their flexible electrochemical cells and their manufacture.

The patent abstract is as follows:

A thin printed flexible electrochemical cell, and its method of manufacture, using a “picture frame” structure sealed, for example, with a high moisture and oxygen barrier polymer film and featuring, for example, a printed cathode deposited on an optional, highly conductive carbon printed cathode collector with a printed or a foil strip anode placed adjacent to the cathode. A viscous or gelled electrolyte is dispensed and/or printed in the cell, and a top laminate can then be sealed onto the picture frame. Such a construction could allow the entire cell to be made on a printing press, for example, as well as gives the opportunity to integrate the battery directly with an electronic application, for example.

Detailed descriptions cover the construction of the cells, sizes and thickness of the “frames” to contain the electrolyte and typical materials that can be used. Examples of a 14 step process are given and then ways to reduce the steps to a 9 step process for a more cost effective operation.

The first claim is quite broad but has many components:

1. A device comprising a flat, thin electrochemical cell for generating an electrical current, said cell including:

a first substrate layer comprising a polymeric film and an oxide barrier layer having a gas transmission rate that permits gas to escape;

a second substrate layer comprising a polymeric film and an oxide barrier layer having a gas transmission rate that permits gas to escape;

a cathode layer provided on at least one of said first substrate layer and said second substrate layer;

an anode layer provided on at least one of said first substrate layer and said second substrate layer;

an electrolyte layer in contact with said cathode layer and also in contact with said anode layer;

and a frame provided substantially around a perimeter of said cell and connecting said first substrate layer to said second substrate layer;

said frame together with said first and second substrate layers defining an inner space that encloses said electrolyte layer and at least portions of said cathode and anode layers.

This image from their website gives some idea of the size.

Printed battery

 

 

 

 

 

 

 

 

 

If you require more details or need to understand the patent landscape for this technology contact me or add any comments below.

Carbon Nanotube patent granted for Canatu Ltd

Canatu Ltd (Finland) has been in the news recently after receiving an investment of €4.7 M to fund its production development.  I was particularly interested to see whether they had been granted any patents from their portfolio of applications on carbon nanotubes and what new applications have emerged.

Background on Canatu:

Founded in 2004, Canatu is a spin-off from the Helsinki University of Technology (now Aalto University). Canatu’s business is the production and sales of a new class of versatile nanomaterial based films and components.

Canatu has developed a novel form of carbon, namely NanoBuds™, and a new way to directly produce high value components on any substrate from this material by Direct Dry Printing™. These components improve the performance and reduce the cost of optical and electrical devices and diminish their environmental footprint. Canatu is currently developing its flexible thin film NanoBud™ components and production processes to supply display, touch, photovoltaic, tracking and haptic customers in the optics, energy and electronics sectors.

Granted Patent:

The NanoBud™ technology (a molecule having a fullerene molecule covalently bonded to the side of a carbon nanotube) is described in the granted patent EP1948562B1.

This patent was granted with the main claim reading:

Claim 1. A fullerene functionalized carbon nanotube, comprising one or more fullerenes and/or fullerene based molecules bonded to the carbon nanotube, characterised in that the bond between said fullerenes and/or fullerene based molecules and said carbon nanotube is covalent and is formed on the outer surface wall and/or inner surface wall of said carbon nanotube.

Further details are claimed around the size of the fullerene and how it is covalently bonded.  The CNT can be a single, double or multi-walled nanotube and can be formulated as a solid, liquid, gas or paste, deposited or synthesized on a surface.

There is also claimed a method for its manufacture:

Claim 9. A method for producing at least one fullerene functionalized carbon nanotube comprising at least one fullerene and/or a fullerene based molecule covalently bonded to the outer surface and/or inner surface of said at least one carbon nanotube,characterised in that the method comprises: providing at least one catalyst particle to a reactor heated to between 250 and 2500 °C; providing a gas flow to said reactor wherein the gas comprises at least one carbon source; providing at least two reagents including CO2 and H2O, or precursors thereof to obtain the concentration of H2O between 45 and 245 ppm and the concentration of CO2 between 2000 and 6000 ppm. releasing carbon from the carbon source into or onto one or more catalyst particles in the presence of the reagents; and collecting said at least one fullerene functionalized carbon nanotube comprising at least one fullerene and/or a fullerene based molecule covalently bonded to a wall of said at least one carbon nanotube.

The additional method claims include details around the catalyst (very broad) and the reagents (can be an etching agent) and the carbon source.  Finally the last three claims relate to the way the material is used to create a functional device.

21. A functional material, wherein the function of the material is at least one of field emission, light emission, electric conduction, thermal conduction, fuel cell, battery, metal-matrix composite, polymer-matrix composite, capacitor, electrode, transistor, diode, drug molecule carrier characterised in that it comprises at least one fullerene functionalized carbon nanotube according to any one of claims 1 to 8.

22. A thick or thin film, a line, a wire or a layered or three dimensional structure, characterised in that it comprises one or more fullerene functionalized carbon nanotubes according to any one of claims 1 to 8.

23. Using one or more fullerene functionalized carbon nanotubes in accordance to any one of claims 1 to 8 in preparation of a device.

Fujifilm files patent for flexible solar cell technology

Fujifilm used to be a major competitor when I was involved in photographic film and plate manufacture for Kodak.  It is interesting to see that they have converted their expertise in these areas to the fabrication of flexible Aluminium based films for solar cell technology.  In a recent announcement Fujifilm Corp announced they have formed a CIGS photovoltaic (PV) cell on an aluminum flexible substrate and achieved a conversion efficiency of 17.6% with an aperture area of 0.486cm2.  Also, they confirmed a conversion efficiency of 12.5% with an aperture area of 72cm2.

Interestingly a US patent application (US20100224249) appeared just a few days ago covering this technology.  Fujifilm used anodic oxidation to form an aluminium oxide (Al2O3) layer on an aluminium foil as the substrate which is treated with a diffusion barrier layer of either titanium or chromium. On the substrate, a molybdenum (Mo) layer, CIGS layer, cadmium sulfide (CdS) layer and zinc oxide (ZnO) layer are stacked. Furthermore, sodium doping is used to increase conversion efficiency.  Full details can be found in their concrete examples 1 and 2.  A comparison with an example not containing the diffusion barrier layer had a lower conversion efficiency.

The Millenium Technology Prize for 2010 awarded to Prof. Michael Grätzel

The 2010 Millennium Prize Laureate Michael Grätzel is the father of third generation dye-sensitized solar cells. Grätzel cells, which promise electricity-generating windows and low-cost solar panels, have just made their debut in consumer products.  The technology often described as ‘artificial photosynthesis’ is a promising alternative to standard silicon photovoltaics. It is made of low-cost materials and does not need an elaborate apparatus to manufacture. Though DSC cells are still in relatively early stages of development, they show great promise as an inexpensive alternative to costly silicon solar cells and an attractive candidate for a new renewable energy source.

The key patent describing Grätzel’s invention was first filed as a GB patent with a priority date of 17th April 1990.  The technology was published in Nature in 1991 and the first patents were granted in 1994.  US5350644B1 was published on 27th Sept 1994 and has now been cited by over 70 other patents indicating the significance of this invention.  However, it was not until 2009 that mass production of the solar cells began.

The opening sentence of the patent very simply states the essence of the invention: “The invention relates to new transition metal dyestuffs and to their use in photovoltaic cells. These dyes can be coated on titanium dioxide films rendering such devices effective in the conversion of visible light to electric energy”

The first claim reads as follows:

  1. A solar-light-responsive photovoltaic cell comprising a first electrode comprising

    i) a light transmitting electrically conductive layer deposited on a glass plate or a transparent polymer sheet;

    ii) at least one porous, high surface area titanium dioxide layer applied to said light transmitting electrically conductive layer;

    iii) a dopant applied to at least the outermost titanium dioxide layer, optionally also to the second to the outermost and third to the outermost layer, said dopant being selected from a divalent metal ion, trivalent metal ion, and boron; and

    iv) a photosensitizer applied to the dopant-containing TiO2 layer, said photosensitizer being attached to the TiO2 layer by means of interlocking groups, said interlocking groups being selected from carboxylate groups, cyano groups, phosphate groups and chelating groups with conducting character selected from oximes, dioximes, hydroxy quinolines, salicylates, and α-keto-enolates.

Wake Forest University: Patent granted for Fibre-Solar Cell Technology

EP2022108B1 was granted last year and provides the University with a first patent for a new solar-cell technology that can double the energy production of today’s flat cells at a fraction of the cost.  The patent on the technology has been licensed to FiberCell Inc. to develop a way to manufacture the cells. The company, based in the Piedmont Triad Research Park in downtown Winston-Salem, is producing its first large test cells.

The new solar cells are made from millions of miniscule plastic fibres that can collect sunlight at oblique angles – even when the sun is rising and setting.  Flat-cell technology captures light primarily when the sun is directly above.

A diagram from the Fibercell website shows the design structure of the fibre:

First Claim:

1. An apparatus comprising

an optical fiber core (102);
a first electrode (104) surrounding the optical fiber core (102);
at least one photosensitive organic layer (108) surrounding the first electrode (104) and electrically connected to the first electrode (104); and
a second electrode (110) surrounding the organic layer (108) and electrically connected to the organic layer (108).
characterized in that
said first electrode (104) is radiation transmissive.

According to Wake Forrest, to make the cells, the plastic fibers are assembled onto plastic sheets, with a technology similar to that used to create the tops of soft-drink cups. The absorber – either a polymer or a dye – is sprayed on. The plastic makes the cells lightweight and flexible – a manufacturer could roll them up and ship them anywhere cheaply.  A diagram of this arrangement maybe similar to the one found in the patent in Fig. 5 but no details of the manufacture are available.

Flexible e-Paper Modules for Displays

AU Optronics unveiled a 20-inch e-paper display at the recent  FPD2009 (28 Oct 2009) along with their 6-inch flexible e-reader  They claimed this was the world’s largest e-paper display that can be mass produced and so I was interested to see what technology was being used and what patents had been granted.  It turns out that AUO are working with technology developed by Sipix and a quick look at the Sipix website provides a nice summary of the Microcup® technology and its use for electrophoretic displays.

The first patent applications for this approach were filed in 2000 but the granted patent that covers this technology is US7112114B2 which was published on 26th Sept 2006.  The first claim reads:

1. A process for the preparation of a semi-finished display panel, which process comprises the steps of:

a) coating a layer of a thermoplastic, thermoset or precursor thereof on a temporary substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a temporary substrate layer followed by removing unexposed areas, to form an array of microcups;

b) filling the microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture;

c) top-sealing the microcups; and

d) applying a conductor layer or a permanent substrate layer onto the top-sealed microcups.

Fig. 6 from the patent shows a schematic of the process: