United States: Determination Of Obviousness/Inventive Step In United States Of America


Non obviousness is one of the essential patentability requirements to obtain a patent in United States, as stated under section 35 U.S.C. § 103. The purpose of including a non-obviousness requirement is to encourage innovations that are not mere combination of prior art, without any technical advance.

Title 35, United States Code 103(a):

A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art, to which said subject matter pertains.


The U.S. Patent Act of 1952 added 35 U.S.C. § 103, which effectively codified non obviousness as a requirement to obtain a patent. Hotchkiss vs. Greenwood, 52 U.S. 248 (1850), was the first US Supreme Court case to introduce the concept of non-obviousness as patentability requirement. Prior to the patent act 1952, novelty and utility were the only grounds for patentability. The Supreme Court first attempted to articulate the process for determining non obviousness in Graham v. John Deere (1966). The Court held that non obviousness could be determined by:

  • Determining the scope and content of prior art
  • Analysing the differences between the prior art and the claims at issue
  • The level of ordinary skill in the pertinent art
  • Evaluating evidence of secondary considerations. Secondary considerations include commercial success, a long felt but unmet need for a device, and the failure of others to solve the particular problem addressed by the invention in question.

Further, the Supreme Court in KSR v. Teleflex case identified a number of rationales to support a conclusion of obviousness, which are consistent with the proper "functional approach" to the determination of obviousness as laid down in Graham.

Case law:

Teleflex, Inc. sued KSR International, claiming that one of KSR's products infringed Teleflex's US 6237565 entitle "Adjustable pedal assembly with electronic throttle control". KSR argued that claim 4 of US 6237565 was obvious under 35 U.S.C. § 103 and therefore invalid. The district court ruled in favor of KSR, but the Court of Appeals for the Federal Circuit reversed the order in January 2005. However, on April 30, 2007, the Supreme Court unanimously reversed the judgment of the Federal Circuit, stating that claim 4 of US 6237565 was obvious under the requirements of 35 U.S.C. §103.


Combination of prior art elements:

One of the steps to determine obviousness is to articulate whether the claimed invention is a result of mere combination of prior art elements. It is always desirable to find, if a person skilled in the art can come up with the claimed invention by combining the elements of known methods, wherein each element would have performed the same function as it would have separately.

Sundance, Inc. v. DeMonte Fabricating Ltd is a hallmark case for revocation of patent based on aforementioned statement. Sundance, Inc invention was related to a segmented and mechanized cover for trucks, swimming pools, or other structures.

Sundance, had sued DeMonte Fabricating Ltd for infringement of their US patent 5026109. However, DeMonte Fabricating Ltd argued that claim 1 of US patent 5026109 was invalid and obvious citing two prior art references.

The first prior art reference taught a reason for making a segmented cover with ease of repair, in which a single damaged segment could be readily removed and replaced when necessary. A second prior art reference taught the advantages of a mechanized cover for ease of opening.

The Federal Circuit noted that the first reference and the second reference would perform in the same manner it would have individually, even after combination. Therefore, it was obvious for a person of ordinary skill in the art to expect that addition of replaceable segments as taught by the first reference to the mechanized cover of the other would result in a cover that maintained the advantageous properties of both of the prior art covers.

Substitution of elements to obtain predictable results

Substitution of an element by another element (analogue) performing similar function is considered as one of the grounds for determination of obviousness. In re Fout, 675 F.2d 297, 213 USPQ 532 (CCPA 1982) had claimed decaffeinating coffee or tea from fatty material. In re Fout, had substituted an evaporative distillation step for separating caffeine from oil. However, prior art disclosed an aqueous extraction step (Pagliaro) and direct distillation process (Waterman) for decaffeinating coffee or tea from fatty material. The court stated that both Pagliaro and Waterman taught a method for separating caffeine from oil and therefore, it is obvious for a person skilled in art to substitute a method for another performing similar function.

Known technique to improve similar devices:

A method is said to be obvious if it enhances a particular class of devices (methods, or products) known in the prior art by using a known technique.

In re Nilssen case, the invention was directed to a means by which the inverter can be disabled if current exceeded pre-established threshold level for a specified period. The United States Patent and Trademark Office Board of Patent Appeals and Interference rejected claims 1-4, 9-11, and 16 of Nilssen's patent application Serial No. 476,150 on the ground of obviousness citing two prior art references as provided below:

The first prior art USSR Certificate No. 729,738, described a device for indicating the high-load condition via a control means in an inverter, but did not indicate the specific manner of overload protection.

The second prior art U.S. Patent No. 3,305,793(Kammiller) disclosed disabling the inverter circuit by means of a cut off switch if there exist a high load current condition.

The federal circuit stated that it would have been obvious to one of ordinary skill in the art to use the threshold signal produced in the USSR device to activate a cut off switch to render the inverter inoperative as taught by Kammiller.

Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results

Applying a known technique to a known device (method or product) for improvement of the device, and finding that the results obtained over such improvement would have been predictable by a person of ordinary skill in the art can be considered as obviousness. Nilssen case can be cited in this context as well.

Obvious to try

The concept of "obvious to try" is a quite sensible requirement for determination of obviousness. "Obvious to try" can be examined as follows:

  • The need for designing the claimed invention to solve a problem being recognised at the time of invention.
  • Existence of a finite number of known solutions for the problem recognised
  • Implementing one of the known solutions, which is obvious to a person skilled in the art for solving the problem recognised.

Pfizer, Inc. v. Apotex, Inc

Pfizer had been selling amlodipine besylate drug in tablet form under the trademark Norvasc® in U.S. At the time of invention of amlodipine besylate, amlodipine (Apotex) was known to posses similar therapeutic properties as were claimed by Pfizer for amlodipine besylate. Pfizer however, argued stating that amlodipine besylate had better manufacturing property as compared to amlodipine.

Court's decision:

The court found that a person skilled in the art would have obviously tried to formulate the salt form of the compound, if he had problems with the machinability of amlodipine and would have been able to narrow the group of potential salt-formers to a group of 53 anions known to form pharmaceutically acceptable salts, which would be an acceptable number to achieve "a reasonable expectation of success."

Known work in one field of endeavor may prompt variations of it for use in either the same field or a different one based on design incentives or other market forces if the variations are predictable to one of ordinary skill in the art

The scope and content of the prior art, whether in the same field of endeavor as that of the applicant's invention or a different field of endeavor, including a similar or analogous device should be identified to examine obviousness. Further, design incentives or market forces prompting to adaptation of the known device (method, or product); the differences between the claimed invention and the prior art encompassed in known variations or in a principle known in the prior art are important aspects for determining obviousness relating to the claimed invention. In addition to the above mentioned criteria for determining obviousness, it is also essential to know how a person with ordinary skill in the art, in view of the identified design incentives or other market forces, would have implemented the claimed variation of the prior art, and how would have been the claimed variation predictable to a person of ordinary skill in the art.

The claimed invention in Ex parte Catan, 83 USPQ2d 1568 (bd. Pat. App. & Int. 2007) was a consumer electronics device using bio authentication for enabling sub users to place orders up to a preset maximum credit over.

The first prior art (Nakano) disclosed a consumer electronics device like the claimed invention, which provided security through a password authentication rather than a bio authentication device. The second prior art (Harada) disclosed the use of a bio authentication device (fingerprint sensor) on a consumer electronics device (remote control) to provide bio authentication information (fingerprint). The third prior art (Dethloff) disclosed that it was known in the art at the time of the invention, to substitute bio authentication for PIN authentication to enable a user to access credit via a consumer electronics device.

The Board stated that a person with ordinary skill in the consumer electronic device domain at the time of the invention would have been familiar with using bio authentication information interchangeably with or in lieu of PINs to authenticate users. The Board concluded that it would be obvious to a person with ordinary skill in the art of consumer electronic devices to update the prior art password device with the modern bio authentication component and thereby gain, a secure and reliable authentication procedure.

TSM test

TSM stands for teaching, suggestion and motivation. A claimed invention fulfils the requirement of being non obviousness, if combination of know elements, which forms the invention, not motivated, suggested or taught in prior art.


The very fact that a number of approaches have been suggested to determine whether a proposed invention is obvious or not, is an evidence that determining obviousness is a complex subject. Hence, it is important for patent professionals to be abreast with the subject, so that informed advice can be provided to clients at least based on existing guidelines.

About the author: Hemanth Puttaiah has extensive experience in delivering patent consulting services in the software engineering domain. He has been offering patent specification drafting, patent analytics and patent support services to technology companies and patent practitioners in US and Europe. He has in-depth knowledge of various international treaties governing patent filing and prosecution across the globe, and advises clients on patent strategy. Hemanth started his career as a software engineer, where he worked on several open source technologies. His working experience as a software engineer prior to entering the field of IP has enabled him to add significant value to our clients in the software engineering domain. Hemanth holds a Bachelors of Engineering Degree from University B.D.T. College of Engineering. He is also a registered patent agent.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

*** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.