DISTILLATION ION EXCHANGE MEMBRANES SEMICONDUCTORS

Abstract

Welcome to our archive of more than 2,200 articles. In January, we would like to share an article by Michael Bigwood, PhD, that examined trends in research and the issuance of water treatment patents between 1992-2002. This article was published in the January 2004 issue of Ultrapure Water Journal.

The primary intent of this article is to discuss trends that have occurred in the last 10 or so years in research and development (R&D) activities pertaining to the purification of water for use in the electronics industry.  Companies involved in the field can use this information to benchmark the level and nature of their own R&D programs versus the industry as a whole.

Our information is derived from various bibliometric analyses of patent data, such as historical trends, the frequency of occurrence — or co-occurrence — of patent classifications and assignee ranking.  Our secondary objective is to illustrate how these simple methods make is possible to extract a significant amount of information from a large number of documents without having to resort to a costly, time-consuming full content analysis.

The patent dataset used for this study was created by retrieving from Derwent's World Patent Index database all the records that were simultaneously assigned two specific codes: the Derwent Class "U" capturing all documents pertaining to "semiconductors and electronic circuitry", and the International Patent Classification (IPC) C02F covering "treatment of water, waste water, sewage or sludge".  The resulting dataset contained 879 records for the full period covered by the database (1963 to 2002).

For the trend analysis discussed in the beginning of the next section, we have counted the number of basic patents in the dataset that were issued, on an annual basis, from 1992 until 2002.  Without getting into too much detail, let us just point out that counting basic patents in the Derwent database, as opposed to filings in all designated countries, ensures that one count represents one invention. 

Classifications assigned by both the examiners and Derwent to the records in the database provide information about the record’s content.  By tallying the frequency of occurrence of the codes assigned to a dataset, one can develop an understanding of its content without having to read each of the documents it contains.  This approach has been used in the second part of the “Results” section to track, over time, the changes in the relative weight of patenting activity for various water purification techniques and in the “Areas of Use” section to develop an understanding of the specific areas of the electronic industry's unit operations for which water purification methods are being developed.

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