Monthly Archives: October 2014

Patent Law for the Lay Person: What do the Words in a Patent Claim Mean?

An Article in Schott, P.C.’s IP Law For Start-ups Series
By Stephen B. Schott


Almost weekly, I have a conversation with someone who looks at a single patent drawing or abstract and asks me how someone could get a patent for “that.” I am happy to explain that the inventor didn’t get a patent for what’s in the abstract or drawing, but for what’s in the claims. At the end of the patent, after the abstract, drawings, and description, is a list of numbered sentences called the claims. The claims are the part of the patent that define exactly what the invention is.

With so much importance invested in the language in the claims, it’s no surprise that courts scrutinize the claims during patent litigation. Multimillion dollar litigations often turn on the meaning of a single word in a claim and this article will review the leading case on patent claim interpretation to shed light on how courts interpret patent claims.

Claim Interpretation: A Matter of Law

Claim interpretation, or claim construction as it is sometimes called, is a matter of law. What that means is that interpreting what the words in a claim mean is an issue decided by a judge, not a jury. Put in the context of a patent infringement trial, the judge will tell the jury how to interpret claims and the jury will decide if an accused product falls within the scope of those interpreted claims.

Usually, a judge will hold a separate hearing from the trial to determine the proper claim interpretation. This hearing is either called a claim construction hearing or a Markman hearing,Markman v. Westview Instruments, Inc. being the Supreme Court case that clearly defined the judge as the person responsible for interpreting claim language.

Given that almost all patent infringement cases turn on the meaning of the claim terms, the judge’s claim interpretation is often dispositive of the case, that is, although the judge makes no decision on infringement when deciding the meaning of the claim terms, the claim construction is often the decision that controls which party wins the case.

How the Judge Interprets the Claims

Claim interpretation is always done not from the judge’s perspective, or even the inventor’s perspective. Judges interpret claims from the perspective of a “person of ordinary skill in the art.”  This person is a fictional construct who has normal skills and knowledge in a particular technical field but is not a genius.

From this person’s perspective, a judge can consider two broad categories of evidence when interpreting patent claims: intrinsic and extrinsic evidence.

– Intrinsic Evidence

The judge must favor the intrinsic sources to the extrinsic ones and absent a specific disclaimer of a claim term’s meaning in the specification, a judge may not need to look any further than the claims’ plain and ordinary meaning to interpret a claim.

The patent specification is the next best source for the meaning of a term after the claim itself. The specification may define the term, provide examples related to the term, or may describe the state of the prior state of the art that helps define the term.

Similarly, the record of the patent’s prosecution at the US Patent and Trademark Office may provide evidence of meaning, disclaimer, or what a term means when compared to other references.

– Extrinsic Evidence

The judge can consult extrinsic evidence sources but should generally give them less weight. The rationale for this is that undue reliance on extrinsic evidence poses the risk that it will be used to change the meaning of claims, and one of the critical reasons for claims is that they provide an important public notice function that lets others know the scope of the patent right.

– Dictionaries

Dictionaries are a special case in patent claim interpretation. Technically, they are extrinsic because they don’t make up the patent or its prosecution record. But when a judge wants to look up a word definition, even to determine its plain meaning, where better to look than a dictionary, which provides an objective reference for the words?

Judges have been cautioned by appellate courts not to overly rely on dictionaries but they remain an oft-cited resource for judges determining claims’ plain and ordinary meaning.

Case Review: Phillips vs. AWH Corp.

The leading case that explains how to properly interpret claims is Phillips vs. AWH Corp. The technology in the case involved temporary prison enclosures. One of the figures from the patent is shown below.

As you can see from the figure, one of the enclosure’s is a sloped steel wall that was helpful in deflecting bullets. This feature became the source of much debate, because the accused product did not have sloped walls but instead uses walls at right angles.

Looking at the claim, the yellow highlighting below is the element related to these walls.

Specifically, the judge had the task of interpreting “internal steel baffles extending inwardly from the steel shell walls.” Phillips, the patent owner, asserted that this language does not specify that the walls are at a specific angle. AWH argued that the walls must extend at an acute or obtuse angle to deflect the bullets effectively.

Taking up the issue, the appellate court (the Federal Circuit Court of Appeals that hears all patent appeals) noted that the claims are silent as to angles, and looked to the specification noting that:

  • “the baffles are described as providing structural support,”
  • “In Figure 7, the overlapping flanges “provide for overlapping and interlocking the baffles to produce substantially an intermediate barrier wall between the opposite [wall] faces,” and
  • “Those baffles thus create small compartments that can be filled with either sound and thermal insulation or rock and gravel to stop projectiles.”

The court described that one of the canons of claim construction is that every claim is presumed valid and thus every claim is assumed to have a different scope. Following this logic, the court noted that there were several other claims that specified angled baffle walls, which implies that no such angular limitation existed in the highlighted language above.

Given that the baffles had purposes other than stopping projectiles and that the claim language itself was not limited as to the angle of the walls, the court concluded “that a person of skill in the art would not interpret the disclosure and claims of the ’798 patent to mean that a structure extending inward from one of the wall faces is a “baffle” if it is at an acute or obtuse angle, but is not a “baffle” if it is disposed at a right angle.”

That’s a summary analysis of how a court interpreted a claim in a single case. If you have questions about other claim construction cases, I would be happy to consider them for a future article.

If you have questions, contact me.

If you want IdeaEsq delivered to your inbox, sign up for the daily or monthly newsletter.


Nobel Prize Awarded for the Blue LED: What is it?

By Stephen B. Schott

20131011153017!Nobel Prize

The Nobel Prize in Physics is usually awarded for a Star Trek-sounding discovery or invention like Giant Magnetoresistance. But this year’s award recognizes an invention that we use every day:  the blue LED. You may have one in your pocket or nearby right now. In fact, you’re probably staring at millions of them as you read this.

Before LEDs Part 1: The Incandescent Bulb

Before exploring the LED and blue LED, let’s visit the incandescent bulb that lit the 20th century using the simple principle that things glow when they get hot. In an incandescent light bulb, electricity passes through a conductive wire to a tungsten filament 6 feet long wound up to an inch or so length in a typical bulb. As electricity passes through this filament, electrons move between higher and lower energy states—and on each movement to a lower state, the electrons give off photons, some of which result in significant visible light.


All of that creates a few problems. One problem is that to get significant visible light from a light bulb requires that the tungsten be heated to about 2,200C/4,000F and at such extreme temperatures, tungsten combusts. The air-tight bulb prevents combustion because it seals the bulb from oxygen. No oxygen, no combustion. One problem solved.

The next problem is that all the electricity passing through the tungsten filament causes vibration—this vibration releases tungsten atoms and degrades the filament, making it thinner and thinner until it breaks. The next bit of genius is that the gas inside the bulb is an inert gas called argon.

Remember the periodic table—argon was one of the special noble gasses way out on the right that don’t react with other elements. As tungsten atoms shake free of the filament, they have nowhere to go because the inert argon gas won’t react to it—having nowhere to go, most of the tungsten atoms return to the tungsten filament, slowing its breakdown.

The problem with the incandescent bulb is that only 10% of the energy it uses results in visible light. The remaining 90% of the energy is given off as invisible light and heat, which makes the incandescent bulb an effective but inefficient light source.

Before LEDs Part 2: The Fluorescent Bulb

Enter the fluorescent light bulb, which is probably above you if you’re reading this in an office. These are those long tubes usually paired together in drop ceilings.


Fluorescent bulbs act on the same principle of exciting atoms and jumping electrons between higher and lower energy states. The fluorescent light bulb has two electrodes, one at each end of the tube, that release free electrons into the tube. The free electrons collide with the mercury atoms in the tube, causing the mercury atoms’ electrons to move between higher and lower energy states. Just as with the incandescent bulb, this movement between states releases photons.

But the genius in the fluorescent bulb is that not only does it release visible light from the photons, it makes certain invisible ultraviolet light that we normally cannot see visible by the use of a phosphor coating on the inside of the tube. When a photon hits a phosphor atom, one of the phosphor’s electrons jumps to a higher energy level. When the electron falls back to its normal level, it releases energy in the form of photons that are visible as white light.

Fluorescent bulbs are 4-5 times more efficient than incandescent bulbs but they still release significant amounts of heat and invisible light. Fluorescent bulbs also use mercury, which is toxic.

Part 3: Enter the LED

An LED works using a semiconductor material to transmit electricity across it. Semiconductors are just what their name suggests: They have varying degrees of ability to conduct electricity, and usually are made from a poor conductor with intentional impurities introduced into it in a process called doping.

The typical conductor material used in LEDs is aluminum-gallium-arsenide, which when pure, has no free electrons across that conduct electrical current. But when engineers introduce impurities into the material, the impurities create free electrons (negative charges) and also positive holes where the electrons can go. The free electron material is called an N-type material, and the positive hole area is called a P-type material.

When a battery applies voltage across the LED from the N-type material to the P-type material, electrons begin to move from a depletion zone between the N- and P-type materials to either end of the charged LED (each end having a positive or negative charge). As the electrons and positive holes move, elections “find” the positive holes and when they do, they fall to a lower energy state and give off photons in the form of visible light.

LEDs produce light at about 10 times the efficiency and have a lifetime of about 50 times as long as an incandescent bulb.

Part 4: Enter the blue LED

As you may recall from above, when an electron falls from a higher to a lower energy state, it gives off photons and given the right materials, it gives off photons that have a frequency visible to the human eye. Different light frequencies produce different colors but before this year’s Nobel Laureates came along, LEDs came in just two colors: red and green, which were the results of semiconductor material choice. And while red and green can be combined to make a lot of different colors, they can’t be combined to make white light, which is what we humans are most comfortable with. Imagine reading by red light: You could do it but you wouldn’t be happy.

visible spectrum

Scientists knew that the way to make a reliable white light was to make a blue LED. Professors Akasaki, Amano, and Nakamura knew that the solution lay in using gallium nitride as their semiconductor material in the diodes and they tackled the problem of making gallium nitride crystals of a size large enough for practical use. Professors Akasaki and Amano from Nagoya University in Japan solved this problem by designing a micro-scaffold made partly from sapphire. Professor Nakamura made a similar breakthrough while he was working at the chemical company Nichia. where he created a temperature manipulation process to grow the crystals.

From their discovery, the blue LED became a possibility, and using the blue LED, many people are now able to experience white LED lights, like the kinds in LED displays, long-life flashlights, camera flashes, and even the light on the back of your phone.

If you have questions, contact me.

If you want IdeaEsq delivered to your inbox, sign up for the daily or monthly newsletter.