http://www.earthtimes.org/articles/show/66578.html

I wonder why they waited so long to do this. Their needs to be some new laws put in place because people should be filing lawsuits immediately after they find out that someone is steeling their design.

I bet Microsoft and Toshiba is watching this case very closely because although the most likely scenario is that the case would end in a settlement and that’s if Sony wrongfully infringed on Target’s patent but if it goes to far, this could be the only chance HD-DVD can survive.

[url]this could be the only chance HD-DVD can survive.

In my opinion, I don't think this lawsuit will make or break HD-DVD.

HD-DVD will stand on its own merits.

So much is splitting hairs. I am sure there has been metal gold films for years, maybe it is an variation that is patented, as such Blu-ray might be relying on another previous patent, or just happened to come up with the same thing. The reason for the late application could be that they only just realised this (as the detail could have been buried in trade secrets/agreements) or, speculatively, have been waiting for Blu-ray to become too committed to go back to the drawing board, there can be an number of reasons, none has to be dishonest.

This "technology" is not the protective coating... it is the reflective layer. I know Han Nee, founder of Target Technology. We used to work together at CBS Records which was bought by Sony. He was a researcher at CBS Labs in Milford, CT. He was let go by Sony when they closed CBS Labs. Han developed this technology in the early days of DVD... it took him a couple of years, and he was remarkably persistent.

The reflective layer on dual-layer DVDs used to be pure gold. Only gold had a high enough reflectivity, along with the ability to be sputtered evenly across the surface of the disc. The obvious problem with using gold - it's too expensive. Even though the thickness of the reflective layer on the disc is measured in microns, the cost per disc for gold was something like 10 to 15 cents. The whole DVD manufacturing industry was looking for a better alternative. Silicon can be used, but the sputtering vacuum chamber has to be shut down more frequently when you use silicon... and it makes the disc harder to bond (glue the 2 halves together). Pure silver can be used, but silver is very reactive ... prone to oxidation (tarnishing). Even though the reflective layer is found on the inside of the disc (in the center of a DVD or HD DVD, or covered by a 0.1 mm thick cover layer on a Blu-ray disc), any traces of oxygen can cause corrosion. If the bonding isn't perfect, the silver can start to tarnish, and the reflectivity drops in these areas (causing a loss of signal, and readability).

Han Nee experimented with silver alloys... mixtures of silver with a little bit of copper or other metals. These alloys are nearly as cheap as silver, and they have similar reflectivity. They sputter well, and they are less prone to oxidation (more corrosion resistant). So they are the best alternative for the reflective layer on DVDs, HD DVDs and Blu-ray Discs.

Han's patent is very broad... protecting just about any silver alloy for this purpose. If competitors can't prove prior art, or find some other reason to invalidate the patent they will simply have to pay to license the technology or choose a different material for the reflective layer. I don't think this cost is significant in the big picture... a fraction of a penny per disc.

Tom

Tom, thanks.

Obviously the alloy neutralises the corrosiveness of the silver content, but has anybody thought of alternative ways. I remember one way of producing rust resistant steel (not silver I know, but just an example) by cold dipping, in late 80's I think. Steel rusts because of charge in the surface, this changes the charge and it doesn't rust. Could similar things be done with silver or other metals? I am curious if anybody has ever been able to make aluminium corrosive resistant, I wonder what an fine trace of gold would do.

The major disc manufacturers and equipment manufacturers have certainly been looking for a better material to use for the reflective layer on DVDs, HD DVDs, and Blu-ray discs.

You have to keep in mind that the reflective coating is applied in a machine that is integrated with several other machines as part of a "replication line". These systems include the injection molding machine, fully automated handling systems, the metalizer (that applies the reflective coating), a bonding system (that glues 2 DVD substrates together to form a DVD)... or a cover layer system that applies the cover layer on a Blu-ray disc, and a disc inspection system.

The metalizer is a vacuum chamber that creates a plasma in a magnetic field, causing a precise amount of material to be "sputtered" from a target (a disk of metal) to the plastic substrate. The whole process takes only a few seconds. For single-layer discs, the amount of material has to exceed a minimum thickness in order to provide reflectivity above a minimum specification. For the bottom layer of a dual-layer disc, the reflectivity must be controlled to around 30% (allowing the player to read through the bottom layer - layer 0 - to the top layer - layer 1). The chosen material has to work well in this process. Each material will have different properties when you try to sputter it onto a disc. Aluminum is used for CDs and single-layer DVDs, but it doesn't have a high enough reflectivity for dual-layer DVDs or the new formats. Gold is an ideal material with high reflectivity and extreme corrosion resistance. Silver works fine, but it relies on the bonding or coating material to keep it hermetically sealed inside the disc.

It might be possible to improve corrosion resistance by adding another layer to the silver, but the second layer of material would add another step to the process (adding another machine, increasing costs and decreasing efficiency).

Tom

I see, so it would have to be an external treatment, that was an simple quick, almost concurrent, process to establish the lattice structure and seal the holes. What I was suggesting was more simple, doping like process, though another layer could neutralise the charge and hold the structure. Thanks for the feedback Tom.

Sorry I misread the case when I posted this thread.

Here is another patent suit against Sony.
http://www.betanews.com/article/Certicom_Patent_Suit_Against_Sony_Threatens_to_Unravel_AACS/1180557165

First Sony gets In trouble for their game pad, then Terget is after them for the way they make their Blu-Ray discs, now Certicom wants part of the action.

Talking about patent disputes is so unprofitable, except in illustrating how misguided and broken, and dubious, the patent system and examples are, or what dubious things people get up to in patent violations. There is an lot of hairsplitting alongside too broad ranging controls and claims, to the exclusion of the majority of potential players, the smaller players.

I wonder if the patent system will last another ten or twenty years, controlling business oriented reforms are really shooting themselves in the foot. In the long term such biases, dysfunctionality and frankly inequity are going to cause an substantial backlash, I am not talking about just further reforms, but an replacement of the system. I tried to figure out an proposal for an more equitable system myself in the past, and it could be done in much better ways.