The impact of lower Indium prices on the Transparent Conductive Films market

October 15, 2015 1 comment

It has been quite some time since I last posted something on this blog. I landed a long-term consulting contract at the beginning of this year that involved integrating both digital printing and vacuum coating technologies in a production environment. Added to this mix was the fact that my employer was in a start up venture mode serving a market, which itself was still evolving. It was a very interesting assignment and I learned a lot. However, as is the case with many consulting agreements, cash flow issues resulted in the termination of my contract. I was not surprised since consultants, usually considered a discretionary cost, are usually the first to go when the financial horizon gets cloudy. The fact that our cost and services usually do not involve any overhead burdens seems to be forgotten when the going gets rough.

Anyway, I did try to keep up with the conductive, transparent thin film (TCF) market while working on this new assignment. As always in this ever-evolving technology, much has happened during the last 6 months while some things remaining the same. I will try to cover some of these changes in the next few blogs. This blog will be concerned with one of the main arguments that is constantly used against ITO based coatings; that is the cost of ITO/PET makes it the most expensive TCFs there is.

Since ITO/PET has been in use for over 30 year, its properties and costs are well documented and known throughout the industry. This is not the case with many of the other competitive products. All I can ever find in the literature are comments such as “less expensive than ITO.” I have never been able to fully document if these comments are just about the purchase price, or do they include the overall cost involved in the production of the product that uses the TCF. In addition, how does this “cost” compare with ITO when the overall performance is also considered? I do wish I could afford one or two of the many market studies that have been done over the years that claim to include cost calculations for all of the TCF’s. (As an aside, I also would like to count the number of studies that have been released on TCF’s in the last few years!). But, these studies are usually priced much too high for an individual to buy one of them, much less several.

The reason I am bring up this cost comparison, is that in 2015 the price of In, probably the single largest component in the cost of making ITO sputtering targets, has dropped dramatically. In now costs in the range of $250-$300 per kilogram. A year ago, the price was approximately $700/kg. The main reason for this decrease is the collapse of the Kanya metals exchange in China. This exchange, which is now under government investigation for fraudulent money borrowing practices, was artificially controlling the price and limiting availability of In for several years.

Surely, the cost of In based priced sputtering targets has directly tracked this price reduction. This should be reflected in the reduction of the cost component of ITO/PET material in any product that uses it. Can the other competitors now claim to be enough “less expensive than ITO” to justify replacing ITO/PET in the market. It will be very interesting to now track how the predictions in the use of all the TCFs in the future change given this significant price reduction in In. I am sure that each application will find the right price/performance metric that works best for it. I have always held that each TCF technology will find niche markets where it is the best choice. It will be interesting to see how the lower price of In affects these choices. Hopefully, I will be able to report on this in future blogs.

John Fenn

President, Fennagain

23775 Harwich Place

West Hills, CA 91307

(Office) 818 888 8649

(Cell) 818 400 2781

E-mail: johnfenn@att.net

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A long sabbatical

April 15, 2015 Leave a comment

Greetings,

Even though this is supposedly a blog about thin film materials, I am going to touch upon a totally different subject in this addition. To be completely above board, I just posted a very similar comment to a LinkedIn group. I hope any readers that happen to be members of this group and my blog site do not mind the duplicity,

What do you think of this title?

“Europe’s Component Obsolescence Group developed a Total Obsolescence Management Tool for estimating the effectiveness of obsolescence planning.”

After reading through the article associated with this title several times, I finally realized that it was all about depreciation. This is a concept that I was taught when I started on my first business assignment. The US government lets you depreciate some significant expenses over time so that, ideally, you will put aside enough money to replace an item when it is obsolete. You can do straight line, accelerated, declining, etc depreciation, depending on your business philosophy or the state of your market. But it is all about planning ahead.

For capital equipment the time frame can be 3-10 years, depending on the market and equipment design. For computers and software, the depreciation time can be as short as 1 year. Or, I usually chose to just expense smaller computer costs because of the fast pace of change in this industry. Even owners of professional sports teams can depreciate the salaries of their athletes when they buy the team. (No wonder the selling price for some teams seems too high!!)

Unfortunately, most companies I have been associated with ignore the savings part and just take the write off to improve their bottom lines. This type of shortsightedness in business planning is a continuing big problem. However, to create a group, another word for the dreaded word “committee”, to develop a Total Obsolescence Management Tool to help estimate the effectiveness of obsolescence planning (Try typing this 5 times fast!) for Europe (I assume this is for the (Common Market) seems like a bureaucracy run rampant!

I think I will apply for a grant to create a task force to determine the effectiveness of the application of common sense to business.

What do you think?

Best regards,

John Fenn

President, Fennagain

23775 Harwich Place

West Hills, CA 91307

(Office) 818 888 8649

(Cell) 818 400 2781

E-mail: johnfenn@att.net

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Other TCF Materials

November 28, 2014 Leave a comment

Other Transparent Conductive Thin Film Candidates for Use in Touch Panels (Continued)

Oct. 31m 2014

I have discussed several different TCF candidates in previous articles. This blog covers some of the other available approaches that are not yet “mainstream” but show promise.

Carbon nano tubes (CNT) have been around over many years. The history of their discovery is outlined in some detail in Wikipedia. Their novel structure results in very high electrical conductivity among many other intriguing properties. Single walled tubes (SWCNT) had even higher electrical conductivity then the more abundant multi-walled tubes. Just as is the case with Ag NWs, the large aspect ratios of CNT (~ 1 micron long by ~1-2 nm diameter) allow for dilute mixtures of SWCNTs to be used to form a TCF. These films have a grey black tint due to the inherent flat absorption of visible light by CNTs. This absorption limits how thick of a layer of SWNTS, or how concentrated a suspension of CNT inks, can be used as a TCF. The graph below shows the typical %T vs. Rs data for Toray’s CNTs, some of which are now being used in commercial e-paper or PCAP TPs.

This graph is from Toray’s website, 2014

The grey color of a semi transparent film of CNTs can act as a neutral density filter for the display upon which it is mounted. This feature allows for improved readability in higher background light environments such as the outdoors. CNT based TCFs are very flexible and can be bent or stretched repeatedly without losing conductivity.

Costs for these films have not come down as low as originally forecast. One reason is that the SWCNTs used in TFCs have to be further processed to separate them from the multi walled tubes that are made along with the single and double walled CNTs in the manufacturing process.

Outside of Toray’s commercial offerings, Canatu, a Finnish based company, is probably the best know producers of CNTs used in TGFs. Their CNTs, called NanoBuds™, are made with a small nodule, or “Bud,” attached to the wall of the nanotubes. Canatu claims that their Carbon NanoBuds™, or CNBs, have “superior electrical, mechanical, thermal and chemical properties” to those of standard CNTs. The CNBs are produced using a new, single-step manufacturing process that combines the “aerosol synthesis of CNB material and R2R deposition by their Direct Dry Printing®”. Images of the CNBs are given below.

Taken from Canatu’s website

Recently Canatu signed their first touch panel manufacturing license for CNBs with CN Innovation.

As mentioned earlier for CNTs, Canatu is emphasizing in their advertising that a TCF made from CNBs provides improved contrast enhancement for a display/TP module that uses NanoBuds™, when viewed in bright light backgrounds.

One down side of using any CNT is that lasers are the only practical way to pattern them. This process is not nearly as fast and cheap as the subtractive or additive processes used to pattern other TTCF materials.

A “self assembly” of silver nanoparticles is another possibility for making TCFs. This material is made by depositing a suspension of Ag nanoparticles in a somewhat volatile carrier onto a substrate’s surface. When the carrier liquid starts to evaporate the layer starts to break up into smaller domains. As the liquid in the droplets evaporate further, the nanoparticles agglomerate around the edges of the droplet. With the correct carrier liquid, this process can take about 30 seconds. The effect is the same as that which forms coffee rings when liquid coffee evaporates. Thus, a more common name for this type of TCF is “coffee” or “coffee cup” rings. After complete evaporation of the carrier liquid, the remaining film is a random mesh of interconnection rings. Shown below is a picture sequence published by Cima NanoTech that illustrates this drying process as it forms a lattice of conductive lines.

This type of TFC film, called Sante® by Cima NanoTech, was first introduced by in the early 2000’s. They licensed the technology to Toray a few years later. Toray has recently shown images on the internet of prototype rolls of a film they call “New TCF” that has the same random matrix of lines as found in Sante®. Because of the structure of the matrix, the inherent visible light absorption of Ag nanoparticles and the thickness and height of the traces, Sante® might be limited in the display/TP configurations for which it can be used. Cima NanoTech reports that their FS 200 film has an Rs of < 25 ohms/sq. and a %T between 85%-88% dependent of the substrate type and the Rs. They have shown a TP mounted on a 42” diagonal display made from their Sante® film. See the microscopic images of a typical Sante® below:

More recently, Cima NanoTech reached an agreement with Sabic to produce Sante® coated polycarbonate substrates. Along with its strong impact resistance, this polymer has excellent flow properties near its melting point. This means that a polycarbonate sheet can be easily bent, at reasonably low processing temperatures, in three dimensions to make a preformed part, such as a curved dashboard inset for cars and trucks. Since Sante® can be flexed and stretched quite a bit without losing conductivity, an electrical circuit using Santé can be printed on a flat polymer sheet and then formed into a complex shape. For example, it is possible to print a complex circuit with multiple connections on a flat substrate; adding several components on the sheet and then formed it in three dimensions before it is mounted in the dashboard. This would eliminate the need for attaching several flex circuits to different flat substrates (needed to conform to the curved dashboards being used now) after they are attached behind the structural frame.

C3Nano, who has been working for the last couple of years to develop their own version of a random matrix of Ag NWs, has just announced the availability of new TCF named Active-grid™. According to C3Nano Active-grid™ is a AgNW based mesh that has been stabilized into a “singular grid” by fused the Ag NWs together using a “Nanoglue” process. According to C3Nano, this process involves “the reorganization of conductive materials using redox chemistries.” The fusing process significantly lowers the contact resistance of the wires at the junctions of the mesh. Because of this lower resistance, fewer wires are need to reach a given Rs. Fewer wires results is lower haze values and a higher % T for the desired ohms/sq. value.

Initial results for a 50 ohm/sq. coating deposited on PET film are 0.7% haze level at 91% T. A 100 ohm/sq. coating has a haze level of 0.1%. At 15 ohms/sq. the % T is >85%. The Active-grid™ based films can withstand multiple flexing and stretching without losing electrical integrity. They have successfully coated both sides of PET films and can coat glass substrates as well. As is the case the other Ag NW based layers, the grid is protected from handling by a clear polymer over coat. Both chemical etching and lasers can be used to pattern the films for use in PCAP or resistive TPs.

C3Nano just announced a $12 million third round funding drive that was led by Nagase America Corp as well as an undisclosed “large cap global industrial company. I was told that they are currently in production for their material and expect to be able to make enough “ink” within the year to coat millions of sq. M. With this investment C3Nano as raised over $22 million since its start.

Several other new ideas for TFCs have been published since I began this series. A team of scientists from Akron University, led by Dr. YU Zhu, recently published an article describing how they used “electrospun” fibers as a mask to create a patterned network of metal nanowires on either glass or PET substrates. Their initial results are a Rs of 6 ohms/sq. at 83% T and 24 ohms/sq. at 92% T. It was not indicated in the abstract of their paper how the substrate was accounted for in the % T measurements. The TCF was reported to have passed numerous “scotch tape” tests. Touch panels were made from the PET coated substrates. They claim the process can be scaled, but so far only laboratory samples have been made.

A company out of Israel, Clear Jet, has published an article about using “inkjet silver nanoparticles drops” to form very well defined “narrow invisible rings” of conductive materials. They call this an enhancement of the “coffee ring” based TCF films made by Cima NanoTech. They claim that other layers, such as transparent “conductive jumper” ink lines between isolated rings can easily be printed on the same substrates. No performance specifications were given in this release.

Finally, Konica Minolta showcased a metal mesh TCF made by an inkjet process at the Display Innovation 2014 in Yokohama, Japan held Oct. 29-31. The metal lines were 5 microns wide. The film showed at the exhibit had a resistance range of 0.3-5 ohms/sq. and a % T of 83%. There was no mention of the substrate used. They claimed that this mesh was made with at “high speed” inkjet technology, something that would be difficult to do with conventional inkjet technologies.

In summary, there have been a number of new TCF materials and concepts introduced recently that range from laboratory samples to full production. Many of these are interesting technologies and all claim to be “better” than ITO/PET with respect to flexibility, ultimate cost and lower Rs values. However, the markets in which they wish to compete are getting increasingly competitive. For example, Wintek, one of the larger TP and LCD manufacturers in Taiwan, declared bankruptcy on Oct. 2014 due to “pricing pressure” in the TP market.

Through all of this, ITO/PET still seems to be the current king of the TCF mountain with a firm grip of its position. Several market forecasts report that ITO/PET should maintain a majority share of the TCF market through 2018. The fact that it has existed for so many years with a well-entrenched manufacturing capital base and a solid record of performance makes it hard for design engineers to ignore. There are numerous niche markets in which the other TCF candidates can prove their performance and actual cost benefits. However, until they have a built up a solid performance record, ITO/PET will still command high respect.

On the other hand, there are other touch technologies that have been developed, which already are having an impact in the market. These are the in-cell, on-cell and OGS approaches. They are being used in a number of commercial touch products now, including Apple’s iPhone and iPad. As overall production yields increase and their cost basis comes down, these none film designs will continue to win market share. Finally, progress continues to be made in gesture recognition, which does not require actual physical touch. Whether or not ITO/PET will finally be retired to the “old and out dated technology” closet, it will have had a long and exciting run while making a lot of money along the way.

John Fenn

Fennagain

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Where is the Touch Panel Industry Headed?

September 18, 2014 Leave a comment

Where is the Touch Panel Industry Headed?

John Fenn of Fennagain Sept. 18, 2014

I ran across an article written by Digitimes’ Research Staff written about a week ago reporting on O-Film’s latest financial results. O-Film is one of the largest touch panel manufacturing companies in China. The company reported a drop of 5.91 percentage points in the first half of 2014 profits when compared to last year’s performance. It was also noted in this article that over the last year the demand by the portable computer device industry for shipments of fully laminated TP/ display modules has sharply increased.

O-Film reported that almost 50% of their last quarter’s shipments of 12-15 million units were these fully laminated units. They had to buy the majority of the LCD units they used from outside sources while ramping up their own in house capacity. Obviously, having to buy LCDs from outside suppliers had a negative impact on their profits. They expect to double their own LCD display capacity from 2 million to 4 million units by the end of 2014. However, they will still have to supplement their internal production by purchasing several million displays well into 2015. Digitimes reported that the company is willing to take this significant hit in their profits in order to maintain their leadership position in touch panels in China.

It was also reported a few months ago that O-Film had joined up with Synaptics to develop a finger print recognition system for use in Chinese smartphones in 2015. In this same article, O-Film was reported to have stated that they will ramp up their overall touch panel business even more in an attempt to reach a greater number international customers during this same time.

In several other recent news articles it was said that some major display manufacturer companies, being led by LG. are now aggressively pushing their own touch/display modules throughout Asia. If this becomes the norm then those touch panel companies who manufacture just the touch panel are going to experience yet another profit squeeze. Many of these companies have already cut back expansion plans and/or mothballed existing touch production lines.

Finally, more and more experts in the field are reporting that “gesturing” is going to replace physical touch as next technique for interacting with and controlling computers. Given the success of Sony’s Wii play station it would seem natural to assume that control by gesturing will become increasingly popular, especially for larger displays.

So, my original question of where is the touch panel industry headed seems to be gaining in relevance. Display manufacturers are already using “in cell” and “on-cell” TP designs to try and save money by eliminating TP manufacturers from the supply chain. With manufacturing yields continuing to increase for these two TP concepts their use should continue to increase.

Maybe the simple answer to the question is that the TP industry will start to move away from TCF coated films at an increasing rate and that the manufacturers of these materials will have to be satisfied with filling niche markets.

Personally, I think that the smaller displays, say those with diagonal < 5”, will continue to use PCAP TPs for the near term and that the TCF of choice will remain ITO. There is just so much invested in the use of ITO in this market that it will be difficult to justify the investment any large amount of new capital and development time to qualify and use other materials. The ITO/PET industry has already shown its ability to lower prices to remain competitive. As ITO/PET production equipment starts to become fully depreciated, these prices can fall even lower and still remain profitable for those companies with facilities already in place. But I do not see any real expansion in the ITO/PET business being driven by the TP business as it is now structured. Unfortunately, all of this means that the possible consolidation of the TCF industry could be a growing storm cloud in the horizon.

John Fenn

Fennagain

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Update on Metal Mesh Production

August 29, 2014 Leave a comment

Update on Metal Mesh Touch Technology

Fennagain Blog August 28, 2014

I read today that the Taiwanese government sponsored Industrial Technology Research Institute (ITRI) has developed what they call a “one step” roll to roll (R2R) production process to make metal mesh based TP patterns in high volume. While this “breakthrough” was announced at the Touch Taiwan 2014 exhibit that ran from August 27-29, 2014, ITRI and their printing equipment partner, Komori, had revealed their joint efforts for this project in Oct, 2013 at the 2013 FPD International Show held last year during October in Japan.

The significance of this development is that they can R2R print lines < 10 μ R2R on various substrates ranging from 300 mm to 500mm. ITRI is claiming that this new technology will allow for mass production of TPs ranging from 3.5” to 11.6” diagonal at a cost reduction up to 30%.

ITRI said that this new R2R printing method can give the Taiwanese TP manufacturers an advantage in the ever increasingly competitive touch market. The Mainland Chinese TP industry has been rapidly gaining market share in this business over the last couple of year and have announced that they plan on having the majority share of this market by 2017. If Taiwan can protect the IP for this new printing method, Mainland China’s ambitious plans might be delayed for awhile. But how long can Komori hold off making equipment sales in other Asian countries? It would be nice to know the terms of this JV development program.

The other interesting aspect of this breakthrough is that the announced sizes for the new R2R printing equipment lay right in the middle of the TP size domain in which ITO has been so firmly entrenched for the last few years. The use of pre patterned printed mesh based TP sheets will eliminate several production steps that are needed to incorporate ITO/PET films into TPs. If all the other properties of this printed mesh based material stand up those of ITO/PET, then ITO/PET will lose even more of its near term market share. Nitto Denko, who holds ~ 80% of the ITO/PET market for PCAP based TPs, recently lowered their film prices by 20-30%. How much lower can they go before they start to take a serious hit on profits?

I would like to get some other peoples comments on this news. Please let us know your opinions on where you think the TCF market for TPs is going.

Dr. John B. Fenn Jr.

Fennagain — Inspiration and Implementation with a Dash of Common Sense

23775 Harwich Place

West Hills, CA 91307

Tel: 818 888 8649

Cell: 818 400 2781

Fax: 818 888 3543

E-mail: Johnfenn@att.net

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Other Transparent Conductive Thin Film Candidates for Use in Touch Panels

August 26, 2014 3 comments

Other Transparent Conductive Thin Film Candidates for Use in Touch Panels

August 22, 2014

In several earlier blogs I have discussed the use of ITO/PET and metal meshes/PET (MM) as transparent conductive films (TCF) in touch panels (TP) and other flexible optoelectronic applications. ITO/PET is still the number one choice for use as a TCF. But, it is slowly losing market share to other TCF solutions as the TP market continues to expand and come up with applications where ITO/PET cannot compete. For example, it appears as if ITO/PET cannot provide low enough sheet resistivity (Rs) at a high enough “water white” transmittance (T) for TPs with diagonals > 300 mm. Also, it has very limited flexibility. MM can easily provide acceptable Rs TCFs for this market segment and are experiencing a rapid growth in popularity as was discussed in one of my earlier blogs. The other approach that appears to be a serious competitor in this area is silver nanowires (Ag NW).

Ag NWs have been around for many years. Cambrios, probably the best know company in this area, was issued their first patent in this area in 2006, although they had been working on Ag NWs as a company it was spun out of UC Santa Barbara in 2002. Ag NWs can be made with have very large aspect ratios of length vs. width, usually 40 to 50 nm in diameter vs. lengths of 10’s of mm. When a suspension of these Ag NWs is coated onto a substrate, usually PET film, they form a random mesh of overlapping wires. Due to their large aspect ratios, only a small concentration of Ag NW is needed to form a conductive layer with a Rs in the range of 10-20 ohms/sq. (ops) with a % T > 85%, including an optical grade PET film substrate. Thus they have acceptable properties for use in larger diagonal TPs. The network of nanowires is usually over coated with clear organic based protective layer to protect the TCF during handling. A microscopic image of Cambrios’ ClearOhm®, found on the internet, which shows the conductive matrix of Ag NWs, is given below.

Some advantages of Ag NWs are:

· They do not require a vacuum system, like ITO/PET to be made. The large cost of vacuum manufacturing systems is a major factor in the cost of ITO/PET.

· They are coated using standard solvent coating techniques, usually by slot dye.

· Due to the low concentrations of Ag NW needed to make a continuously conductive film, the overall cost of the product should be low.

· They can be patterned either by laser ablation or by chemical etching. The etch process is designed to selectively removes the Ag NW leaving the over coat in place. This is an advantage in reflected light. The coating can be flexed or stretched without losing Rs.

Some possible disadvantages of Ag NWs are:

· Difficulty in keeping the haze level of the coating to be > 1%. The majority of the haze comes from the cross over points of the wires. These points can become large if the diameters of the wires are too large or multiple wires cross over at the same place. A multiple wire node can be seen in the image given above. Multiple cross over nodules occur at higher rates as the conductivity is lowered

· It is not clear if the projected low costs, said to be at least 20% lower than equivalent ITO/PET films, have yet been reached in practice.

· The longer term environmental stability of these films, if they are exposed to “regular” air pollution conditions and/or UV light exposure, is of concern. One supplier of these films, Carestream, has stated publically that they use anti oxidant stabilizers in their protective over coats to protect their Ag NWs.

One thing that I struggle with regarding Ag NWs is that even though they have been around for sometime there has been little publicity or news released about their successful uses when compared to other TCF technologies. This is a much different situation, for example, when compared to the flood of product releases and news covering the use of metal meshes over the last six months. Yes, Samsung announced in June, 2014 that it was making another “strategic investment” of $10 million in Cambrios in addition to its original investment of $5 million in 2011. Yes, In Dec. of 2013 3M announced the launch of a “3M patterned silver nanowire” film for TPs that uses Cambrios’ inks. Yes, there was the announcement in Oct. 2013 of a major “expansion of the joint venture with TPK and Nissha to bring ClearOhm® Film to market”. Yes, there was the Oct. 2012 announcement and trade show demonstration of a ClearOhm® based 23” touch panel made by LG and used in the LG V325, ‘a new Windows 8-certified all in one PC monitor. But, in comparison to all the other TCF candidate materials, very little is being publically discussed either by the press or the end users of Ag NW based products.

Unlike Cambrios, whose stated mission is to sell only Ag NW inks, Carestream, another major player in the of Ag NW TCF arena, is selling coated film to the market under the name “Flexx Films”. In this way, the end user does not have to find a converter to coat the ink. Carestream also manufacturers its own Ag NWs. From several conversations with Carestream personnel at various trade shows, it would seem as if they are concentrating their current sales and marketing activities in Mainland China. However, there is very little public information from the press or Carestream about the success of this effort. But, if I was going to introduce a new TCF and look for as many opportunities as possible for commercializing it, I would definitely concentrate my efforts in Mainland China. Many experts in the field of TCFs and TPs are predicting that Mainland China will be the leading producer of TPs by 2017.

It could easily be the case that I have missed many of the press releases about the use of Ag NW in TPs or other optoelectronic products. However, I do make an effort to search the internet every day for news on TCFs and subscribe to several news services that cover electronics in general and optoelectronics specifically. I just wonder what, if anything, might be holding back the growth of this technology in the market. I would love to find out that I am wrong and be told about a “slew” of products and applications that are using significant amounts of Ag NWs. If you know anything different about this, please send in your comments to this blog, so that anyone who follows it can also be set straight.

There are several other TCF materials of note. One of these is conductive polymers of which PEDOT:PSS is the main choice. PEDOT:PSS inks are really suspensions of small spheres of these materials in a carrier, usually an aqueous based solution, which are coated by various standard ways onto substrates and then dried.

Here is a schematic of a PEDOT:PSS sphere.

Courtesy of Heraeus

These coatings have been used for many years as transparent non metallic humidity independent anti static conductive coatings. A major market for these coatings was movie films. In fact, Eastman Kodak won an Oscar for this development that was so important to the movie film industry. Providing transparent antistatic coatings for packaging and handling of sensitive electronic and medical components is another large market. Literally tons of this material is made every year.

Agfa, with its Orgacon brand and Heraeus with its Clevios series of inks are currently the two main suppliers of these inks. Also, Eastman Kodak, who uses Clevios inks, sells rolls of coated PET films directly to the TP manufacturers. There are also several other third party converters that will provide coating services for these inks for the end users.

Because conductivity of PEDOT:PSS films depends upon particle to particle contact, it takes a relatively “heavy” concentration of these inks to make a continuously conductive layer. As a consequence of this, these films cannot be made much below 150 ops before their T drops below 85%.

Some advantages of the PEDOT:PSS based TCFs are:

· They are definitely less expensive to make than ITO/PET since they do not require expensive vacuum equipment and are made using standard solvent coating technologies.

· They are flexible.

· Their haze level at 150 ops is < 1.0 %.

· They can be patterned by either laser ablation or chemical “denaturing” by using printable chemical oxidizing solutions. This latter process is adventurous as it requires no removal of the PEDOT:PSS layer so that the patterning is invisible in either reflected or transmitted light.

· Since they are applied as a solution, the films can be used as planarizing agents to smooth rough surfaces as well as to make mesh constructions continuously conductive within the network.

· Their energy levels are a good match for those of OPV materials allowing for a more efficient thin OPV solar cell.

· They are readily available with a reliable supply.

Some possible disadvantages of PEDOT:PSS based TCFs are:

· The transmission for Rs below 150 ops is less than other TCFs and falls off rapidly.

· In the past there have been some reports on instability of the coating upon exposure to UV light and some chemical agents. But newer formulations show a much lower sensitivity.

· The coating has a blue tint, becoming very noticeable at lower ops.

· Some reports indicate that PEDOT:PSS is incompatible with some OLED materials for longer term uses.

Since this note is becoming too long, I will discuss several other TCF candidates in a future blog. The most interesting one of these, carbon nanotubes (CNTs), appears to have arisen from the dead to be experience a second coming out party. Until then, try to remember that a little common.

John B. Fenn Jr.

Fennagain — Inspiration and Implementation with a Dash of Common Sense

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Wearable Electronic Watches

August 14, 2014 1 comment

I recently read an article that compared the many options that the new “wearable” electronic watches were bringing to the market. 30 different models were listed; something I thought was amazing by itself, since Samsung only offered the first commercially available one late in 2013. The reason why I was interested in this article is the same reason why I am writing this note for my thin film blog. The technology of transparent conductive films is a key component for many of these devices. So, I like to keep up with the end markets to make forecasting a little less like reading tea leaves.

When I finished the article I was overcome with the feeling of “WHY?” I do not want to appear as yet another cynical "stuck in the mud" senior baby boomer, but I think way too much hype is being generated by the "smart watch" community for these devices. Since it appears as if sales of the “top tier” smart phones are starting to plateau, the electronic device manufacturing community must be trying to generate a new market frenzy to get us all to jump on the “wearable electronics” bandwagon. But I don’t see that this particular wagon has any itinerary!

Maybe I do need another portable device with a wireless link to my smart phone, but it is not as obvious to me as to why. Yes, it would be nice to have my watch unlock my car and allow me to start it without a key. But wait a minute, my car key already does this! Yes, it would be nice to track my heart rate accurately. But wait a minute; I have been counting my pulse with my finger and a watch for years. Unless a device fits snuggly directly over a blood vessel ALL the time, the resultant heart rate will not be accurate. Yes, it would be nice to have a portable GPS device. But wait a minute; my smart phone has this already. If I am wearing a pair of Goggle Glasses I will have 3 GPS devices telling me where to go, four if I count back seat drivers as well. It is my experience that none of my GPS ever agree what is the best route to go. So now I will have 3 out of four sources telling to take a legal u-turn when I can!

Do I need real another +$100 electronic device to worry about? Many of the watches highlighted in the article had estimated battery lifetimes of only a couple of hours. To use these I need to find a power outlet every few hours to recharge it? The local coffee shop with the most power strips will sell the most cups of coffee! But wait, my smartphone lasts 8+ hours with normal usage and my “electronic” watch lasts several years.

The average display size on these watches is about 1 ½” diagonal. Is this actually large enough to read anything but numbers? Anything but short texts are hard enough to read on the 5 ½” diagonal screen that is in my current smart phone. Touch activation on such a small display will be more difficult than using the “keyboard” on my smart phone. I will not want to carry around a special stylus to use just on my watch!

The speakers in my smart phone are already "low" fidelity. I can’t believe a watch will do any better. I also do not want to plug in ear buds to my watch. They are hard enough to use comfortably with my phone. And, the last thing I need to hear is another of people who are shouting into the watch on their wrist to talk to other Dick Tracey fans. People talking into their smart phones are annoying enough!

Finally will I remember where I last put yet another "useful" small portable device? In most cases, it will probably end up in my top desk drawer along with several other “devices” I was convinced I needed after the novelty wears of in a couple of months. It will probably be joined there next year by another yet even smarter, new and improved “smart” model that my family thought would make a better Father’s day gift than the slippers that I really wanted.. Maybe if the watch had a sensor that would let somebody know I had fallen down while trying to read it in full sunshine, it would be useful. But wait, I think I would rather not fall!

Best regards,

John

Dr. John B. Fenn Jr.

Fennagain — Inspiration and Implementation with a Dash of Common Sense

23775 Harwich Place

West Hills, CA 91307

Tel: 818 888 8649

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