An Analysis of the Apple/Liquidmetal Patent

The prosecution history indicates a hastily prepared application

The claimed subject matter is nothing novel and preempted by the prior art

The news of a joint patent by Apple and Liquidmetal caused significant buzz in the media and euphoria in the market. Suddenly, Liquidmetal alloys are deemed to be producible on a massive scale, and expectations of Liquidmetal alloy in the next iPhone or iPad became widespread.

Let’s have a closer look into this patent, U.S. Patent 8485245, titled “Bulk amorphous alloy sheet forming processes” (Apple/LQMT patent). Note that Liquidmetal alloy is a trade name for bulk amorphous alloy or bulk metallic glass. Based on the case history of the application from USPTO, I present a critical review of the Apple/LQMT patent below.

Let’s start with the original claims as filed to the USPTO. Claim 1 is the primary independent claim this patent is based upon.

1. A method comprising:
pouring a first molten metal comprising a metal alloy at a temperature near or above a melting temperature (Tm) of the first molten metal so as to form a sheet of the first molten metal, wherein the first molten metal has a composition that forms a bulk solidifying amorphous alloy at a cooling rate of 1000 degree C or less,
floating the sheet of the first molten metal on a second molten metal in a float chamber;
and cooling the first molten metal to form a bulk solidifying amorphous alloy sheet, wherein the cooling is at a cooling rate such that a time-temperature profile during the cooling does not traverse through a region bounding a crystalline region of the metal alloy in a time-temperature-transformation (TTT) diagram.

Let me put this claim 1 in layman terms: A method of making amorphous alloy sheet by pouring molten amorphous alloy onto a pool of another molten alloy and cooling it.

This is basically the “float-glass process” (Pilkington process), the primary method to produce modern window glass named after the British glass manufacturer Pilkington. The Apple/LQMT patent is simply about the use of “float-glass process” for amorphous alloys, which is ironically called “metallic glass” in scientific literature.

The Examiner came up with several rejections and remarks. Notably:

Examiner Remark 5:

“…Claim 1 recites “at a cooling rate of 1000 degree C or less.” However, the cooling rate should be given with a unit of “temperature/time”, for example, 1000 degree C/sec. The specification does not provide what the unit of time should be…”

Examiner Remark 8:

“…Please note, however, that if applicant amends the claim to include the unit of time, it will raise a new matter issue, since the specification does not have a support for it….”

The bold sentence was highlighted by the Examiner to emphasize a potentially grave mistake in the patent application.

This is the first red flag on the Apple/LQMT patent. It is not uncommon to have a typo or a mistake in a claim in patent applications. However, having a mistake on a critical unit for the processing of amorphous alloys not only in claims but also in the whole specification is not a small matter. This tells us how hastily this application was prepared. Putting aside the five inventors, who each should have read the specification and claims in their final forms, one expects a much better proof-reading from Apple’s patent attorneys.

If this patent were an important one for Apple, or had any great technological significance, its preparation would have been under much scrutiny and the above-mentioned mistake would not be allowed.

Further on, the Examiner rejected claim 1 based on the prior art McRae (US 2003/0183310):

Examiner Remark 10:

“Claims 1-3 and 7-9 are rejected under 35 U.S.C. 102(b) as being anticipated by McRae (US 2003/0183310).”

To keep short and simple, let me skip the details of the argument by the Examiner and simply quote claim 1 from McRae (US 2003/0183310):

“A method of making a sheet of amorphous metallic material, comprising discharging a molten metallic material onto a surface of a liquid cooling pool and solidifying the molten metallic material on said surface rapidly enough to form an amorphous sheet of said metallic material on said surface.”

Voila! Anyone with some relevant technical knowledge can immediately conclude that McRae (US 2003/0183310) already thought about the float-glass process to make amorphous alloy sheet back in 2002. The Examiner did not miss this and made a strong case to reject the original claim 1 of the Apple-LQMT patent.

Particularly, the McRae (US 2003/0183310) prior art was found and cited by the Examiner. The applicants did not list this important and fatally relevant prior art in their IDS (Information Disclosure Statement). What is IDS? Abbreviated from Wikipedia:

“An information disclosure statement (IDS) refers to a submission of relevant background art to the (USPTO) by an applicant for a patent during the patent prosecution process. There is a duty on all patent applicants to disclose prior art or background information that may be relevant to the patentability of the applicant’s invention. If a patent applicant knowingly fails to submit prior art to the USPTO, then any patent that later issues from the patent application may be declared unenforceable. Furthermore, the duty to submit such relevant information to the USPTO lies not only on the applicant or inventor, but also on any patent attorney employed by the applicant.”

This is the second red flag: Missing a critical prior art in IDS prior to the examination process.

It is plausible that the inventors may not be aware of the McRae (US 2003/0183310) prior art as they are somewhat new to the field of amorphous alloys. I understand and sympathize with them. However, one expects much better from Apple’s patent attorneys as they should have performed a more diligent and comprehensive prior art search.

Again, if this patent were an important one for Apple, or had any great technological significance, its preparation would have been much more deliberate and careful. Any critical prior art like McRae (US 2003/0183310) would have been carefully investigated and listed in IDS by Apple’s patent attorneys.

Furthermore, McRae (US 2003/0183310) is not an obscure prior art. Anyone active in amorphous alloy research in early 2000s would know that Howmet (McRae’s employer at the time) had a DOD funding for the development of amorphous alloy sheet production using float-glass process. The float-glass process is not an easy process to apply to amorphous alloy sheet production as one can see from the abandonment of McRae (US 2003/0183310) patent application.

In the next blog, I will discuss how the Apple-Liquidmetal patent managed to get allowed and whether it has any true technological development or has any value as a patent. The conclusion might be that the buzz in the media and the euphoria in the market are not warranted.

2 thoughts on “An Analysis of the Apple/Liquidmetal Patent

  1. Thank you for your analysis,

    as you say: “The float-glass process is not an easy process to apply to amorphous alloy sheet production as one can see from the abandonment of McRae (US 2003/0183310) patent application.”

    But isn`t the innovative step within the patent, the preferred usage of fusible metals with very low melting temperatures. The McRea patent suggests the tin pool to be maintained “at a temperature of 450 to 500 degrees F”, which may not be low enough to cool down the BMG fast enough. Moreover “by the novel combination of the conveyor and the float chamber would allow the conveyor to rapidly cool the BMG forming metal alloy while the float chamber would be used particularly to provide an excellent surface finish to the BMG sheet”

    The value as a patent might be arguable, but do you think that with a molten fusible metal bath at 60-80°C and a conveyor rapidly cooling down the BMG, a production of BMG sheets might eventually become feasible?

    • McRae suggests the tin pool as an example, not as a limitation. McRae (paragraph 15) says: “For purposes of illustration and not limitation, a molten tin pool maintained at a temperature of 450 to 500 degrees F can be used to rapidly solidify a molten amorphous metallic material.” The Examiner provided more prior art and rejected the use of fusible metals as an inventive step.
      Regarding your second question, whether the teaching of this patent enables BMG sheet production feasible, I will discuss this in more detail in the next blog.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>