{"id":3325,"date":"2025-11-26T01:48:14","date_gmt":"2025-11-25T16:48:14","guid":{"rendered":"https:\/\/sarangip.com\/en\/?p=3325"},"modified":"2026-08-20T14:55:17","modified_gmt":"2026-08-20T05:55:17","slug":"patent-invalidation-unclear-specification-korea-supreme-court","status":"publish","type":"post","link":"https:\/\/sarangip.com\/en\/patent-invalidation-unclear-specification-korea-supreme-court\/","title":{"rendered":"[Expert Column] Can a “Poorly Written Description” Kill Your Patent?"},"content":{"rendered":"\n(Supreme Court of Korea, Dec. 30, 2021, Case No. 2017Hu1298)\n\n\n\n

Imagine this scenario:<\/p>\n\n\n\n

You hired a patent attorney, filed your application, passed the rigorous examination by the Korean Intellectual Property Office (KIPO), and finally received your registration certificate. You feel secure.<\/p>\n\n\n\n

But later, during a patent dispute or lawsuit, the judge tells you:<\/p>\n\n\n\n

“Your patent is invalid because the description is unclear.”<\/strong><\/p><\/blockquote>\n\n\n\n

It sounds like a nightmare, doesn’t it? You might ask, “I paid an expert to write this! How can it be invalid just because of some wording?”<\/em> Unfortunately, this happens more often than you might think.<\/p>\n\n\n\n

In patent invalidation trials, patents are often struck down not because the invention lacks novelty or inventiveness, but simply because the specification (description) was too vague.<\/strong><\/p>\n\n\n\n

Today, I want to discuss why “writing well” is just as critical as “inventing well” in the world of IP.<\/p>\n\n\n\n

<\/div>\n\n\n\n
\n\n\n\n

The “Quid Pro Quo” of Patents<\/h2>\n\n\n\n

A patent is a deal between the inventor and the public. You get a monopoly for 20 years, and in exchange, you disclose<\/strong> your technology to the public.<\/p>\n\n\n\n

Korean Patent Act Article 42(3)(1)<\/strong> mandates:<\/p>\n\n\n\n

“The description of the invention must be clear and detailed enough for a person skilled in the art to easily carry out the invention.”<\/p><\/blockquote>\n\n\n\n

This is known as the Enablement Requirement<\/strong>. If a competitor reads your patent and cannot reproduce the result without excessive experimentation because your instructions are vague, your patent is invalid. It doesn’t matter how ground-breaking the idea was.<\/p>\n\n\n\n

<\/div>\n\n\n\n
\n\n\n\n

A Lesson from the US: The “Simultaneously” Trap<\/h2>\n\n\n\n

Before we look at the recent Korean case, let me share a famous anecdote that haunts every patent attorney.<\/p>\n\n\n\n

There was a US case where a patent was invalidated because of the word “Simultaneously.”<\/p>\n\n\n\n

The court ruled that the term was unclear because it didn’t define how much<\/em> error was allowed. Did it mean “at the exact same microsecond” or “within a reasonable margin”? Because this wasn’t defined, a perfectly good technology lost its protection.<\/p>\n\n\n\n

This pressure is why we, as patent attorneys, obsess over every single word.<\/p>\n\n\n\n

<\/div>\n\n\n\n
\n\n\n\n

The Korean Supreme Court Case: Polycrystalline Silicon<\/h2>\n\n\n\n

Recently, the Korean Supreme Court finalized a decision invalidating a patent for “Method for Manufacturing Polycrystalline Silicon”<\/strong> due to unclear specifications.<\/p>\n\n\n\n

<\/div>\n\n\n\n

The Invention (The Claim)<\/h3>\n\n\n\n

The invention involved a method of producing silicon using a Siemens reactor. The key feature was controlling the process based on a specific formula called the “Archimedes number (Ar).”<\/strong><\/p>\n\n\n\n

The Formula:<\/strong><\/p>\n\n\n\n

\"Korea
Korea Supreme Court judgment cited on patent invalidation for an unclear specification<\/figcaption><\/figure>\n\n\n\n

The Claim:<\/strong> The patent claimed that keeping this “Archimedes number” within a specific range (relative to the Fill Level of the reactor) would optimize silicon deposition.<\/p>\n\n\n\n

<\/div>\n\n\n\n

The Problem: “Parameter Invention”<\/h3>\n\n\n\n

This is what we call a Parameter Invention<\/strong>. The inventor created a new variable<\/em> (the specific Archimedes number calculation) to define the invention.<\/p>\n\n\n\n

The Supreme Court has a strict rule for these:<\/p>\n\n\n\n

“If an invention uses a new parameter or variable, the specification must clearly explain how to measure<\/strong> the values needed to calculate that parameter. If a person skilled in the art cannot figure out the measurement method without excessive experimentation, the patent is invalid.”<\/p><\/blockquote>\n\n\n\n

<\/div>\n\n\n\n

The Verdict: Invalid<\/h3>\n\n\n\n

The Supreme Court ruled against the patent holder.<\/p>\n\n\n\n

Why?<\/p>\n\n\n\n

The formula for the Archimedes number required values for:<\/p>\n\n\n\n

  1. Volume of the Rod (Vrod)<\/strong><\/li>
  2. Temperature of the Reactor Wall (Twall)<\/strong><\/li>
  3. Flow Rate (Q)<\/strong><\/li><\/ol>\n\n\n\n

    However, the patent specification did not explain “how” to measure these specific values<\/strong> inside the reactor during the process.<\/p>\n\n\n\n

    • Where exactly on the wall do you measure the temperature?<\/em><\/li>
    • How do you measure the rod’s volume while the reaction is happening?<\/em><\/li><\/ul>\n\n\n\n

      Since these measurement methods were missing, no one could accurately calculate the “Archimedes number” to reproduce the invention. Thus, the patent was declared invalid<\/strong>.<\/p>\n\n\n\n

      <\/div>\n\n\n\n
      \n\n\n\n

      Conclusion: Drafting is the “Flower” of Patent Law<\/h2>\n\n\n\n

      Ideas, novelty, and inventiveness are crucial. But how accurately and meticulously you describe that idea<\/strong> is equally important.<\/p>\n\n\n\n

      In trademark law, the strategy of “how to file” (to avoid rejection) is the hardest part.<\/p>\n\n\n\n

      In patent law, the strategy of “how to write the specification” (to survive invalidation) is the ultimate challenge.<\/p>\n\n\n\n

      This is why patent drafting is often called the “flower” of a senior attorney’s career. It requires not just technical knowledge, but a mastery of language and logic. A good patent attorney must be a good writer.<\/p>\n\n\n\n

      If you are worried about the strength of your patent specifications or facing a validity challenge, you need an expert who understands these strict requirements.<\/p>\n\n\n\n

      <\/div>\n\n\n\n
      \n\n\n\n

      Sarang IP We provide expert legal counsel on intellectual property disputes and high-quality patent drafting.<\/em><\/p>\n\n\n\n

      \n\n\n\n

      (Disclaimer: This post is for informational purposes only and does not constitute specific legal advice. Please consult with a professional attorney regarding your specific case.)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

      Can a typo kill your patent? Yes. The Korean Supreme Court invalidated a silicon patent due to unclear measurement methods. Learn why high-quality drafting is essential.<\/p>\n","protected":false},"author":1,"featured_media":3907,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[60],"tags":[89,91,90,92,88,67],"class_list":["post-3325","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-insights","tag-enablement-requirement","tag-korean-patent-law","tag-parameter-invention","tag-patent-drafting","tag-patent-invalidation","tag-supreme-court-ruling","category-60","description-off"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t