Contents
Let’s say that an inventor invents a metal teapot with a thermally insulating handle so that the user doesn’t get burned. The inventor’s physical embodiment of the invention is an iron teapot, painted red, with a wooden handle. Not considering prior art for the moment, how would you claim this? Would you claim the red iron teapot with a wooden handle? It should be obvious that the answer is a resounding “no,” since a competitor could produce a noninfringing copper teapot with a plastic handle, for example. If, in a single independent claim, you recited every element and limitation (i.e., an iron teapot, an attached wooden handle, and the teapot is red), then the inventor would have no legal recourse against a copper teapot with a plastic handle. And, forgetting for the moment that colors rarely hold any patentable weight, another competitor could produce a blue iron teapot with a wooden handle which also does not read on the claims.
A “broad” claim would claim exactly what the inventor invented before reducing the invention to practice: a metal teapot with a thermally insulating handle. As a good patent practitioner, you could make this even broader: a thermally conductive teapot with a thermally insulating handle. The narrow aspects, such as the materials used or the color, belong in the dependent claims. Your first dependent claim might be that the thermally conductive teapot is made from iron, your second dependent claim might be that the thermally insulating handle is made from wood, and so forth. You must always consider what a potential infringer might produce when you are drafting claims.
In chapter 1, we discussed the preamble of a claim. The preamble defines the category of the invention and type of invention and is usually consistent with the title of the invention. For the teapot, the preamble might read: “A teapot …” or “An apparatus for heating and serving tea …,” but suppose that the novel metal/wood teapot could also be used for other beverages, or simply for heating liquids regardless of whether they may be consumed or not. Even though we found a broad way to claim the teapot above, we might still be limiting ourselves. We might, instead, choose the invention to be “An apparatus for heating and dispensing a fluid … .” One must consider (a) what the invention is; and (b) how adaptable the invention is to related fields.
A good claim (a) defines the invention for which patent protection is being sought without limiting the inventor to a narrow embodiment; (b) is clear and concise; and (c) is supported by the specification and drawings of the patent application.
Just one more note: Above, I stated that colors are rarely given any patentable weight. If the teapot is blue, red, white, or black, it simply does not matter. The Patent Examiner merely has to find a teapot which is taught as having any color or not even mention color. There is, however, an exception to this: when color actually matters in some material way. For example, a new type of laser that produces “colored” light at a specific visual frequency is obviously important. Scanning equipment usually operates in a narrow range of frequencies, such as infrared, ultraviolet, and so forth. Or, let’s say that by painting the housing of some electronic equipment red, you find that there are “unexpected results” (one of the ways to overcome a rejection under
35 U.S.C. §103, as we will learn later) and that the equipment operates ten times more efficiently with this color paint and no other. That is a scientific/technical feature of significance and, as long as it can be backed up experimentally (with data that goes into the specification of the application), then the color would be a patentable feature.
Consider the chair example from the first chapter. A basic chair of that type will include a seat, at least one leg and a backrest. Assuming for the sake of this example that this is the first chair of that type (i.e., we do not have not have to think about rejections of this chair based on similar prior art chairs), then the broadest possible independent claim will recite just those three elements; i.e., a seat, at least one leg and a backrest. That is the broadest claim that can be made that includes all the necessary elements to make it a complete and fully functional chair. Assuming that the patent application was allowed with that claim, then the owner of the corresponding issued patent could then sue any infringer for making, using or selling a chair with those three elements.
Obviously, one wants the broadest protection possible which, in this context, means being able to sue anyone making, using or selling a chair with only those three elements. This is why we seek the broadest possible claim without making an unworkable device (i.e., if you list so few elements that what you’ve recited in the claim would be unworkable or it would not be clear or well understood how they fit together).
An unnecessarily narrow claim would add elements and limitations which would allow an infringer to easily get around your claims. For example, if in the independent claim, you also added the limitation that the backrest is made of wood, or that it must have a square shape, then someone making an identical chair, but with a round metal backrest would not be infringing. Similarly, if you say that the seat is a “padded seat” in the independent claim, not imagining that anyone would ever want an unpadded seat, and if the patent issues with that limitation, you are then stuck with it. You would not be able to successfully sue someone for making an identical seat with no padding.
Although a practitioner must include all of the basic elements in a claim to make a complete, workable invention, those elements can be made as broad as possible simply by reciting them in the claim as a “seat,” a “backrest,” etc. with no further qualifications. You can include further narrowing details in the dependent claims if you wish, but your overall coverage (i.e., your ability to stop an infringer) depends on what you list in the independent claims, and specifically what words you use there.
Below are three example claims. Claim 1 is written so broadly that it would be rejected for being indefinite because there’s no indication how the elements are linked or how it could possibly be used in just that basic form. Claim 2 is written as broadly as possible but including the necessary elements. Claim 3 is written in such a narrow form that an infringer could simply change one of the narrow limitations and avoid an infringement suit.
1. A chair, comprising:
a backrest; and
at least one leg.
2. A chair, comprising:
a seat;
a backrest secured to said seat and projecting upwardly therefrom; and
at least one leg secured to said seat and projecting downwardly therefrom.
3. A chair, comprising:
a wooden seat having a square contour;
a backrest having a vertical back support portion and a pair of rails extending downwardly therefrom, each said rail having a lower end secured to a rear edge of said wooden seat by a bolt, said backrest being formed from a polymeric material; and
four legs each having an upper end and a lower end, the upper end of each said leg being secured to a lower surface of said wooden seat by a screw, each said leg having a square cross-sectional contour.
Keep in mind that you will often come across issued patents which have narrow limitations. It is entirely possible that the narrowing limitations were inserted via amendments during the prosecution phase of the patent application because the applicant decided they weren’t too limiting for his or her purposes, or maybe simply wanted his or her name on a patent and never had any intention of ever enforcing the patent. Although such situations are possible—and most practitioners have had clients who just wanted a patent to call their own, regardless of whether it was enforceable or not—one should still endeavor to try to claim as broadly as possible just to avoid a potential infringer of Claim 3 from making a circular plastic seat and sidestepping the patent altogether.
U.S. Patent No. 7,846,390 provides an excellent example of apparatus claims, method claims, and means-for language. Below, you will find drawings showing the apparatus, an excerpt from the specification, and the full set of claims as they issued. Please note that these are the final set of claims, not the original claims the application was filed with; that is, these are the amended claims which I was able to finally get allowed. Prior art considerations will be discussed in chapter 9.
If you do not have the technical background to fully follow and understand the excerpt of the specification, just briefly skim it. I will not be focusing on the science behind the invention but, rather, how I chose the essential claim elements and limitations and how I constructed the claims.
Once again, in the below, note that I am using bold face to highlight the sample text and claims from the patent. When a patent application is filed, the text should never appear in bold (or with italics or underlining).
[0045] With reference to Figs. 1 and 2, the apparatus 10 for measuring concentrations of fuel mixtures using depth-resolved laser-induced fluorescence performs measurements on a sample container 14 holding a fluid sample 12, which may be, for example, a fuel mixture. The sample container 14 is formed from an optically transparent and chemically inert material, such as quartz, fused silica, or other material having a high transmittance to ultraviolet radiation (UV) and may be in the form of a conventional cuvette, test tube or the like. In a preferred embodiment, sample container 14 is a quartz cuvette having a length of approximately one centimeter, a width of approximately one centimeter, and a height of approximately five centimeters.
[0046] The sample container 14, containing fluid 12, is mounted on a translatable stage 18, which moves linearly along a first axis. The translatable stage 18 may be L-shaped, including a vertical support and a horizontal support. The translatable stage may be formed from Plexiglas plates or any other suitable material, and holds container 14 through use of a fastener 16, such as a clamp, a flexible, elastic band, or other suitable releasable fastener.
[0047] Translatable stage 18 may be made to move in the path 20 of the excitation light beam in any desired manner. Preferably, the horizontal support of translatable stage 18 is mounted on a track and is actuated to move along the track by stepper motor 19. Stepper motor 19 moves the translatable stage in defined increments of about.16 mm. Alternatively, translatable stage 18 may be provided with mechanical means for moving the sample holder 14 in the path 20 of the excitation light beam. For example, the horizontal support of translatable stage may have a rack mounted thereon operated by a pinion or gear train operable by a Vernier dial, a thumbwheel, a slider or the like, which may be equipped with a precision scale or with detents corresponding to.16 mm increments of movement in the path of the beam.
[0048] As shown in Fig. 2, translatable stage 18 moves towards laser 50, so that the distance between the sample container 14 and the laser 50 increases or decreases during measurement, according to the depth measurements desired. It should be understood that apparatus 10 may have any suitable light source capable of fluorescing fluid mixture 12. However, in the preferred embodiment, a pulsed dye laser is utilized to generate a single-frequency coherent beam, thus reducing the occurrence of backscattering of unwanted frequencies of light. Alternatively, an ultraviolet lamp, such as a Xenon lamp with a monochromator to adjust the excitation wavelength, may be used in place of laser 50. Stepper motor 19 may move stage 18 at any desired speed. However, in the preferred embodiment, stage 18 is moved to produce a resolution of approximately 3.8 increments per mm.
[0049] As shown in Fig. 2, laser 50 generates a laser beam 20, which travels along the first axis to penetrate transparent sample container 14 and generate fluorescence within fuel mixture 12. Laser beam 20 may be shaped and directed by a conventional optical iris 48, formed through a screen 46, as shown. Iris 48 is selected for a desired beam diameter, depending upon the needs of the user. As best shown in Fig. 1, translatable stage 18 moves with respect to support surface 28, which may be, for example, an optical bench, an enclosed fluorometer housing, or the like. A diffraction screen 22 is mounted on support surface 28, so that translatable stage 18 also moves with respect to screen 22.
[0050] Screen 22 has a vertical slit 24 formed therethrough for diffracting the fluoresced light emitted by the fluid mixture 12. The diffracted light beam (illustrated by dashed arrows 30) passes along a second axis, substantially orthogonal to the first axis, and impinges upon a collimating lens 36 to form a relatively and substantially unidirectional light beam 32. Light beam 32 passes through a focusing lens 38 to form a focused beam 34, which is received by monochromator 40. Lenses 36, 38 may be any suitable lenses. However, in the preferred embodiment, lenses 36, 38 are convex quartz lenses. The fluorescent emission is depth-resolved in that only the florescence from a particular depth within container 14 passes through the stationary slit 24 to the frequency separator 40, so that, in theory, only the fluorescence emitted by a thin vertical layer of the mixture in cuvette 14 passes through slit 24.
[0051] An exemplary monochromator 40 is the f/3.4 Applied Photophysics® monochromator. Each frequency component is passed to photomultiplier assembly 42, which includes at least one photomultiplier tube, for producing an amplified analog signal associated with each frequency component. Photomultiplier 42 is preferably a fast photomultiplier. One such exemplary fast photomultiplier is the Hamamatsu® R1564U-07 photomultiplier.
[0052] Each analog signal is received by a signal analyzer 44, which measures the relative intensities of each frequency component in order to determine the chemical composition of fluid 12. Signal analyzer 44 further digitizes the analog signals. One such exemplary signal analyzer is the EG&G® Model 4402 Signal Processor. Each chemical composition contained within fluid mixture 12 produces a particular wavelength spectra under fluorescence. Thus, an analysis of the intensities at the wavelengths produced by scanning the monochromator 40 reveals the chemical components and their relative proportions within the mixture.
[0053] It should be noted that laser 50 may be a pulsed laser or a continuous laser. If a pulsed laser is utilized, then signal analyzer 44 is preferably triggered by the Q-switch of the laser 50. As shown in Fig. 2, the laser 50 may be in electrical communication with the signal analyzer 44. Laser 50 generates a trigger signal so that signal analyzer 44 has an appropriate excitation signal to compare to the corresponding emission signal from photomultiplier tuber 42. One such exemplary laser is a pulsed fourth harmonic YAG laser, having a wavelength of 266 nm. For such a laser, preferably the energy output is held at a fixed value of 5 mJ or 4 mJ, though other energy ranges may be utilized.
[0054] Signal analyzer 44 may analyze signals for each position along the first axis through which stage 18 moves, or may include an averaging routine to average the signals over the entire movement of the stage.
[0055] When a fluorescing liquid sample, such as the fuel oil 12 in container 14, is irradiated with UV radiation, it emits light at a wavelength longer than that of the excitation wavelength. The characteristics of the emitted fluorescence spectrum, i.e., its shape, spectral region, temporal behavior, etc., depend not only on the type and the concentrations of the individual chemical compounds, but also on the geometry of the sample illumination. The bulk of the liquid sample, which may be modeled as a succession of thin layers, each stacked upon the other, receives non-uniform excitation radiations at each layer and, consequently, each layer emits a distinct fluorescence spectrum. The non-uniform excitation radiations associated with each layer occur mainly because of the reduction in the intensity of the excitation laser radiation with path length as the laser light beam penetrates inside the sample, and also because of the reabsorption of the already emitted fluorescence from the adjacent layers caused by the fluorescent emission of one compound occurring at the excitation wavelength of a second compound.
[0056] It should be noted that, in general, fluorescence emission from within a fluid mixture is non-uniform, due to inhomogeneous emission-reabsorption fluorescence effects. The movable sample holder 14 is utilized in order to monitor the variations in the non-uniform fluorescence emissions by either scanning the monochromator 40 emission wavelengths, or by scanning the sample holder 14 depth of penetration of the excitation beam from one end to the other. Due to the ability to scan over the movement of the sample holder 14, apparatus 10 is able to detect minute differences in the concentration of the fuel mixture 12, particularly for oil mixtures, with high accuracy.
[0057] The apparatus 10 may be utilized in two different modes. In the first mode, the sample holder 14 is fixed at a desired depth setting and the monochromator is scanned to obtain the emission spectrum. For the exemplary devices, dimensions and wavelengths given above, the monochromator has a slit size of approximately 1.5 mm and is scanned in the region between 280 nm and 620 nm with a speed of 1.6 nm per second. The second mode is achieved by fixing the monochromator 40 at a particular emission wavelength setting and scanning the sample holder 14 from one end to the other to detect fluorescent intensity from successive thin layers at progressively increasing depths of penetration of the excitation beam. In this mode, and given the same exemplary figures as given above, the stepper motor is chosen so that each point in the signal analyzer 44 corresponds to.16 mm translation of the stage 18 by the stepper motor 19.
CLAIMS
I Claim:
1. An apparatus for measuring concentrations of fuel mixtures based on inducing deep-layer fluorescence and using 90° excitation-emission geometry, comprising:
a source of ultraviolet light for generating an excitation light beam;
a sample holder, an elongated sample container supported by the sample holder and configured to contain the fuel mixtures in the path of the excitation light beam, the sample container having a vertical longitudinal axis, the sample container being formed from an optically transparent material such that the excitation light beam is directed within the sample container along a first direction parallel to the excitation light beam and onto the fuel mixtures;
a screen fixedly disposed adjacent the sample holder and sample container, the screen having a vertical slit defined therein, the vertical slit extending in the same orientation as the vertical axis of the sample container and adapted for diffracting fluorescent light emitted from the sample container along a second direction orthogonal to the first direction of the excitation light beam;
a monochromator disposed in the path of light diffracted through the slit in the screen for filtering the diffracted light to an emission wavelength, the monochromator being successively scannable over a spectrum of emission wavelengths;
at least one lens disposed between the slit defined in said screen and said monochromator, the at least one lens being optically suited for focusing the light diffracted through the slit onto the monochromator;
a photomultiplier, the monochromator being disposed between the slit and the photomultiplier, the photomultiplier generating a test signal proportional to the intensity of the diffracted light;
means for generating a trigger signal proportional to the intensity of the excitation light beam;
a signal analyzer receiving the reference signal and the test signal and thereafter generating an output signal corresponding to the intensity of the fluorescent light emitted from the sample container; and
means for moving the sample holder in the path of the excitation light beam so that the light diffracted through the vertical slit in the screen corresponds to fluorescent light emitted from successively deeper portions of the fuel mixtures contained within the sample container resulting from deeper penetration of the excitation light beam into the sample container.
2. The apparatus for measuring concentrations as recited in claim 1, wherein said source of ultraviolet light comprises a laser.
3. The apparatus for measuring concentrations according to claim 1, wherein said source of ultraviolet light comprises a pulsed laser.
4. The apparatus for measuring concentrations as recited in claim 1, wherein said means for moving comprises a stepper motor coupled to said sample holder, the stepper motor being operative to move said sample holder in precise increments.
5. The apparatus for measuring concentrations as recited in claim 1, wherein said at least one lens comprises a collimating lens and a focusing lens.
6. The apparatus for measuring concentrations as recited in claim 1, wherein said slit has a width of between about.5 mm and 2 mm and the sample container has a front-to-back depth of about one centimeter, whereby light diffracted through the slit corresponds to fluorescent light emitted from a thin layer of the fuel mixture in the sample container.
7. A method for measuring concentrations of fuel mixtures based on inducing fluorescence from selective depths inside the fuel mixtures and using 90° excitation-emission geometry, comprising the steps of:
(a) providing the apparatus for measuring concentrations of fuel mixtures recited in claim 1;
(b) providing a sample container containing a sample fuel mixture;
(c) irradiating a sample container holding a sample fuel mixture with an excitation beam of ultraviolet radiation;
(d) diverting an emission beam of fluorescent light emitted from the sample fuel mixture through a slit orthogonal to the excitation beam, the slit being narrow relative to the sample container in order to test fluorescent light emitted from a thin layer of the sample fuel mixture at a discrete depth of penetration of the excitation light beam into the sample container;
(e) generating an emission spectrum for at least one discrete depth;
(f) generating a spectrum of fluorescent intensities at a single emission wavelength over a plurality of discrete depths; and
(g) comparing the spectra to calibration curves generated from known concentrations of the fuel mixture in order to determine relative concentrations of components of the sample fuel mixture.
8. The method for measuring concentrations according to claim 7, wherein step (c) further comprises irradiating the sample container with a laser beam in order to generate laser-induced fluorescence in the sample fuel mixture.
9. The method for measuring concentrations according to claim 7, wherein step (f) further comprises scanning an emission monochromator while keeping the sample container at a single location.
10. The method for measuring concentrations according to claim 7, wherein step (f) further comprises selectively moving the sample container relative to the slit to a plurality of discrete depths, the fluorescent intensity being measured at each of the discrete depths, the fluorescent intensities being measured while keeping an emission monochromator tuned to a single wavelength.
11. The method for measuring concentrations according to claim 7, wherein step (g) further comprises the steps of calculating a ratio of areas under a pair of emission peaks generated in step (f) and comparing the ratio to a calibration curve of the ratios of pairs of emission peaks for fuel mixtures of known concentration.
12. The method for measuring concentrations according to claim 7, wherein step (g) further comprises the steps of calculating an area under a fluorescent intensity peak generated in step (f) over a range of discrete depths and comparing the area to a calibration curve of areas under fluorescent peaks for fuel mixtures of known concentrations.
13. The apparatus for measuring concentrations as recited in claim 1, wherein the sample container is rectangular and made from quartz.
As noted above, the final version of the claims (i.e., the claims which issued in the patent) is not the same as the original version filed in the patent application. Although considerations of prior art and amendments will be covered in chapter 9, I will note at this point that the original Claim 1 did not include the “at least one lens,” and the “means for generating a trigger signal” were replaced by “means for generating a reference signal.” The method claims which appear in the issued patent are substantially different from what was originally filed, and the odd Claim 13, which should actually appear earlier (in the “apparatus” grouping), was not originally in this order. These changes are the result of the prosecution phase of the patent application; that is, the back-and-forth between the Patent Examiner and the practitioner.
When choosing the essential elements and limitations of a claim, there are two primary considerations: completeness and prior art considerations. The two often go together, fortunately. Although this is not a
Jepson claim, I recognized that certain elements are commonly found in optical concentration measurement systems, such as a sample holder, a light source, a signal analyzer, and so forth. With something like the chair from chapter 1, a knowledge of the prior art is relatively easy: I know from personal experience that chairs have at least one leg, a seat, and a backrest, so if I left it at that, I would be certain to get a rejection under
35 U.S.C. §102. With this system, I had the results of the preliminary patentability search in front of me, thus I was aware that the key distinguishing feature of this system (i.e., what distinguished this from the prior art we found in the original search) was the ability to analyze the mixture by depth within the sample container.
In prior art systems, for the most part, the sample container was held fixed and the concentration of the mixture was determined overall for the entire sample. In this system, however, the sample container was movable such that concentrations at various depths could be analyzed. Thus, I knew that Claim 1, the broadest independent claim, would have to “recite” this feature. This appears as the “means for moving the sample holder in the path of the excitation light beam so that the light diffracted through the vertical slit in the screen corresponds to fluorescent light emitted from successively deeper portions of the fuel mixtures contained within the sample container resulting from deeper penetration of the excitation light beam into the sample container.”
If this is the truly novel feature I want to focus on (no pun intended), then why have the rest of the claim? Because the claimed invention must be complete and functional. If I am claiming a chair, I can’t only recite the element of “a backrest,” I actually have to put everything together so that I have a working and functional invention. A “working” or “complete” chair has a backrest, a seat, and at least one leg. Thus, even if I recognize that a seat and a leg are not new and novel, I must recite them and also give the limitations of how they fit together with the backrest.
In Claim 1 above, it would be improper to recite the “means for moving the sample holder …” without also reciting a sample holder. And the sample holder holds a sample container, so the sample container must be recited, too. But, what am I doing with the sample container? I’m transmitting ultraviolet light through it, so I have to recite a source of the ultraviolet light. I want to analyze that light when it passes through the container, so I need elements for analysis as well. Note that we’re not including every gear and every resistor in the claim. This is our broad claim and includes (a) our novel feature to distinguish the invention over the prior art; and (b) just enough elements to make this a working and functional system. Dependent Claims 2–6 are where we include the narrowing details, such as the option that the light source is a laser, and then even more narrow, that the laser is a pulsed laser.
So, how many elements should a claim have? You begin by looking at the prior art and determining what the novel feature or features of the invention is/are when compared against what was previously known. If only one feature is necessary to distinguish between the invention and the prior art, then the claim must have that one feature as an element or a limitation. If two features are necessary to distinguish over the prior art, then the claim must have those two features. The remaining elements and limitations are added for the sake of completeness. You add only what you need to make an operable claim; any additional features may be added in the dependent claims.
Strictly speaking,
all elements of a claim are
essential, particularly when viewed in light of potential infringement. The so-called “all elements rule” states that “[e]ach element contained in a patent claim is deemed material to determining the scope of the patented invention.”
1 When it comes to patent infringement, there is no such thing as a “nonessential” element; that is, if an element is included within a claim, it must be present in a literally infringing product.
Let’s look at the chair from chapter 1 again. If I recognize that the backrest, having an inverted U-shaped frame, a plurality of vertical slats, and a horizontal slat, is the key distinguishing feature of my invention over the prior art, then I must include these elements in my broad claim. And, in order to make a “complete” chair, I must also add at least one leg and a seat. However, what if that backrest could be used on something which is not a chair as I have envisioned a chair? What if the novel backrest is added to a beanbag chair, for example? If I stuck with Claim 1 as it is (i.e., claiming “A chair”), then if a competitor added the backrest to a beanbag chair, there would be no literal infringement. Thus, I would include two sets of claims in the application: The first set would be Claim 1 as it is, the second set would simply be “A backrest, comprising …” and I would only recite the elements of the backrest itself.
The invention described above lends itself well to method claiming in addition to apparatus claiming. Whereas a chair doesn’t include function beyond moving the chair somewhere and sitting on it, every element in the optical apparatus has a function and goes through some sort of process. First you position the sample, then you irradiate it, then you analyze the spectra, and so forth. These are all method steps.
Claim 7 is an independent method claim, but it is written as a “combination” claim. This is a legitimate way to claim a method, though it is something of a “cheat”: You will note that step (a) provides the apparatus of Claim 1. Ordinarily, I would not do this—if I am starting with some particular apparatus, I will claim the steps: (a) providing element X; (b) providing element Y; (c) providing element Z; (d) moving element X such that it blocks element Y from an ambient light source, and so forth.
However, the apparatus of Claim 1 is a rather long claim, so to avoid having to claim steps (a) though (i) with just “providing” clauses, I folded the entire apparatus into “providing the apparatus for measuring concentrations of fuel mixtures recited in claim 1.” As with Claim 1, described above, the novel feature I chose to claim in this method claim was the analysis of the mixture at differing depths. Similar to an apparatus claim, a method claim must include the preliminary steps to make the claim “complete” and cannot simply recite the one key step.
In both the apparatus claim and the method claim, the strategy of “target claiming” is used. This is your primary strategy in the drafting of all sets of claims: Your first independent claim is the broadest you can make it (dependent upon prior art considerations and completeness), and then each set of dependent claims gets narrower and narrower.
Footnotes — § 3.01.:
Claims should be written as clearly and concisely as possible. The usage of clear and common English words (excluding the necessary legal terms, such as “comprising” and “wherein”) and commonly accepted technical terms (i.e., “terms of art”) is necessary, both to avoid rejections for the usage of indefinite language and also to make it clear what the scope of the patent actually is.
There are many cases where you simply will be unable to find a common term for something. The nature of technology and innovation mean that there will always be new elements or new combinations of elements. Also, you cannot be an expert in all technical fields. If you are trained as an electrical engineer, but you are working on something with mechanical parts, you might not know the specific name for a particular type of joint or gear. It is fine to use generalized terminology, such as “an elongated member” or “an elastic element,” as long as you make it clear in the specification and drawings what you mean. “The claims must be read in light of the specification, the ‘single best guide to the meaning of a disputed term.’ ”
2If you don’t know the name for a particular type of spring and you call it the “elastic element” in the claim, make sure it is clear in the specification and drawings that this is the element you are referring to. Any term which may be seen as ambiguous or unclear must be fully described and backed up in the specification.
Further, in order to avoid a potential rejection under
35 U.S.C. § 112(a),
3 for the claims not being supported by the specification (to be discussed in depth in chapter 8), it is best to use consistent language throughout the specification and claims. If you called an element a “bar” in the specification, don’t call it a “rod” in the claims. If you use a general term like “elastic element” in the claims, go back into the specification and make sure you define what you are talking about. For example, “… an elastic element 20 is positioned between wall 22 and rod 24. Elastic element 20 may be a helical spring, such as that shown in Fig. 2, biasing rod 24 with respect to wall 22, or may be any other suitable type of elastic element.”
A good final check before filing a patent application is to read the claims, element by element, limitation by limitation, and make sure that you can identify each and every element and limitation in the specification and drawings (if you claim it, it must be shown in the drawings).
With regard to the “legal” terminology one might use, the usage of “wherein” and similar terms was discussed in chapter 1 with regard to purpose clauses. A “wherein” clause is used to describe function, operation, or a result that flows from previous structure. It is used when the result follows a recited structure or function. For example, “a bookcase having at least one shelf, wherein the at least one shelf extends horizontally … .” The “wherein” clause is a limitation. It is not “throw away” functional language, it is a proper limitation that narrows the scope of the claims. A “whereby” or “such that” clause, as noted previously, is followed by purpose or function alone, and does not add limitations that are given patentable weight.
In the United States, there is a very strict literalism in claim construction, and the usage of the wrong word or phrase can completely change the meaning of (and interpretation of) a claim. In one particular case, a claim for a method of “flash cooking” at a very high temperature read: “… heating the … dough
to a temperature in the range of about … .” The claim should have read: “… heating the … dough
at a temperature in the range of about … .” The difference in this case is huge, since the claimed invention means the dough must be heated so that the dough itself reaches that temperature, whereas the intention was merely to put the dough in an oven of a certain temperature, with the dough not reaching that ambient temperature. The issued patent did not cover the actual invention because of one careless word.
4Footnotes — § 3.02.:
3 As noted in the previous chapter, what was up until recently known as
35 U.S.C. § 112, first paragraph, is now referred to as
35 U.S.C. § 112(a), following the implementation of the 2011 Leahy-Smith America Invents Act (AIA).
A claim is written as a single sentence. Each claim begins with a capital letter and ends with a period. There is only one period that appears in a claim, and it is at the end:
1. A chair, comprising:
a seat having opposed upper and lower surfaces, the upper surface thereof being adapted for supporting the buttocks of a user;
a plurality of support legs, each said support leg having an upper end and a lower end, each said upper end thereof being mounted to the lower surface of said seat with each said support leg extending downwardly therefrom, each said lower end being adapted for removable positioning on a support surface; and
a backrest having opposed upper and lower ends, the lower ends thereof being secured to the upper surface of said seat, said backrest extending upwardly therefrom, whereby said chair may be removably transported by the user to the support surface for providing the user with temporary comfortable support.
Following the preamble and preceding the transition “comprising” is a comma. Following the transition is a colon. Each element and its associated limitations are written in a pseudo-paragraph style; that is, there is an indent at the beginning and the next element begins on a new line. A semicolon ends each pseudo-paragraph, except for the last, which ends with a period.
The above is an independent claim. The dependent claims follow similar punctuation rules:
2. The chair as recited in claim 1, wherein said seat has a substantially rectangular contour.
3. The chair as recited in claim 1, wherein said backrest comprises:
an inverted, substantially U-shaped frame having an upper portion and a pair of lower ends;
a plurality of vertically extending slats, each said vertically extending slat having an upper end and a lower end, the upper ends thereof being secured to an inner surface of said inverted, substantially U-shaped frame; and
a horizontally extending slat secured to, and extending between, the pair of lower ends of said inverted, substantially U-shaped frame, wherein the lower ends of said plurality of vertically extending slats are secured to said horizontally extending slat.
Note that in dependent claims, there is no comma following the preamble (which begins with “The”—remember your antecedent basis), it follows the claim dependency (i.e., “as recited in claim 1”).
It is very important to remember that claims are not normal sentences. They have a very particular format and do not conform to the usual rules of English grammar. A claim contains only one capital letter (at the very start) and only one period (at the very end). Non-alphanumeric characters are typically not allowed (like quotation marks or parentheses), and trademarks should be avoided.
5 Although one may use initials and abbreviations (if they are defined in the Specification), the Examiner may issue a
35 U.S.C. § 112(b) rejection (indefiniteness). Though one could easily argue over this, there is no reason to waste the time and effort of making such arguments, thus abbreviations and initials should generally be avoided. Exceptions to this latter suggestion would include chemical formulae and initials which are so common that they have practically replaced the full expression, such as “DC current,” for example.
Footnotes — § 3.03.:
5 With regard to trademarks, though they are allowed in the Specification, a trademark in the claims can invoke a
35 U.S.C. § 112(b) rejection as being indefinite.
There are many types of inventions where more than one element will be included, such as the multiple legs of a chair. In chapter 1, to claim the chair, we used the language “at least one leg.” This covers a chair having one leg (a central leg, like a bar stool which is fixed to the floor) or a chair having seven legs. Alternatively, we could have used simply “a leg.” Why? Because if an infringer’s chair has six legs, then the infringing product necessarily has “a leg” (i.e., one leg). It does not matter that the product reads on our claim plus has additional elements (i.e., five more legs). In recent years, patent practice has shifted to using more common terminology, and modern claiming favors “a leg” instead of “at least one,” though both are technically correct. This matter is stylistic and is up to the practitioner.
There are, however, cases where “at least” language is still the modern standard, and this is when a particular element has a plurality greater than one. For example, let’s say that I did not want a bar stool-type structure, and my chair must have at least four legs. Not one, not two, not three, but four or more. Then, we would claim “at least four support legs.”
Often, particularly in mechanical claiming, you will encounter elements of the same type, which have to be distinguished from one another. For example, a machine may have three different rods, all in different places and serving different functions. You cannot claim each one as “a rod” because this would be confusing and would receive an indefiniteness rejection. Thus, the claim would recite “a first rod,” “a second rod,” and “a third rod,” and then each time one of the rods is discussed in a limitation, they are referred to as “the second rod being secured to the proximal end of the third rod”; that is, the full name of the element becomes two words: “first rod,” for example.
Claim 6 in the optical apparatus includes the clause “wherein said slit has a width of between about 0.5 mm and 2 mm and the sample container has a front-to-back depth of about one centimeter… .” In cases such as this and particularly in chemical cases, reciting a range is often desirable. If this were not allowable, and a particular measurement was necessary, one would have to have one dependent claim reciting a width of “0.5 mm,” then the next dependent claim would recite a width of “0.51 mm,” and so on, thus requiring patents to have hundreds or thousands of nearly identical claims. Fortunately, patent law has evolved to the point where ranges are allowed. The “about 0.5 mm” in the range is one of the few places in claiming where “about” or “approximately” would not be determined to be indefinite. This allows you coverage if a competitor comes along and makes a slit that is.49999 mm. Similarly, the depth is listed as “about one centimeter.” This is not a range, but the usage of “about” or “approximately” also goes for measurements.
Although you are allowed to say “about” or “approximately” or define an element as “substantially rectangular”, this is about as flexible as you possibly can be. Anything beyond this level of flexibility would like be deemed “indefinite” under
35 U.S.C. § 112(b). For example, although I can say that a slit has a width of between approximately 0.5 mm and approximately 2 mm, I cannot say that the slit is “relatively thin” and leave it at that in the claim. Why? Because “relatively thin” is what is referred to as “relative language.” In other words, it leaves you with the question: “Thin in relation to what?” And that is in-definite. A range or something which you claim is “approximate” or “about” still has to have something definite attached to it, like a firm measurement: between approximately 0.5 mm and approximately 2 mm. Similarly, if I choose “substantially,” I can say that something is “substantially rectangular,” which may cover something rectangular but with slightly curved corners, but I cannot claim something as “some geometric shape.” Your limitation needs to be far more specific than that.
Under U.S. patent law, relative terms (such as “about” and “substantially”) are not indefinite merely because they are relative. Rather, acceptability of the claim language depends on whether a person of ordinary skill in the art would understand what is claimed in light of the specification. In the case that a relative term provides broader coverage and is reasonably supported by the specification, it may be helpful to argue along these lines if necessary.
In a recent Office Action, I actually did receive a rejection under
35 U.S.C. § 112(b) for using the term “substantially” in a claim, which the Examiner deemed to be indefinite. In this particular case, it simply wasn’t worth fighting over, as removing the word “substantially”
in this particular case did not really affect the claim’s scope. However, if having slightly broader coverage would have made a difference, I would have been able to easily overcome the rejection and retain the original language by referring to MPEP § 2173.05(b):
When a term of degree is presented in a claim, first a determination is to be made as to whether the specification provides some standard for measuring that degree. If it does not, [which is not admitted] a determination is made as to whether one of ordinary skill in the art, in view of the prior art and the status of the art, would be nevertheless reasonably apprised of the scope of the invention.
Although the usage of “about,” “approximately,” and “substantially” used to be relatively easy to use, based on the above, there is a recent trend at the USPTO for an Examiner to either object to its usage or even issue a rejection under
35 U.S.C. § 112(b) as being indefinite because the specification does not define just what that means; i.e., that one of ordinary skill in the art could not simply look at “approximately” and know that, in this context, it means “within a standard deviation” or “plus or minus 2 microns.” Thus, if you are going to use these terms, note that you may have to answer an Examiner at some point, whether he or she is right or wrong, so stating somewhere in the specification just what you mean or, at least, something along the lines of “… it should be understood that these quantities may be varied by any suitable amounts which still result in a purity of over … .”
I once knew a patent attorney who took pride in his verbosity. “It takes me a thousand words just to say hello,” he would always say. I later knew another patent attorney who took pride in the fact that he had an unusually large number of first action allowances in his cases. I never understood either of them, because a long claim or a claim overburdened with elements and/or limitations is also a worthless claim. The shorter a claim is, the more valuable the claim is.
Let’s look at the chair example again. Let’s say that we included every possible limitation and detail in the independent claim that we could. One limitation, for example, would read, “… wherein each said upper end of each said support leg is secured to the lower surface of said seat by a layer of polyvinyl-based epoxy having a thickness of approximately 0.3 mm.” This is obviously a gross exaggeration, but it proves the point well: A competitor could come along and use regular glue, or form a layer that was 1.0 mm thick, otherwise making the same product, and this claim would not cover the competitor’s product. The wordier you are in a claim, the more limitations you are adding, and the more limitations you have, the more narrow is the scope of the claim.
Chemical structures are the only graphical images that one can insert in the Claims. Ordinarily, any graphics and/or images are included in the Drawings section alone, however, in organic chemistry, it is often not easy to describe a chemical composition by a chemical name or a standard alphanumeric chemical formula, thus a graphical image of the chemical structure is allowed. Below is an example:
- A polyzwitterionic acid antiscalant compound, comprising a polyzwitterionic acid having the structural formula:
- A method of making a polyzwitterionic antiscalant compound, comprising the step of performing acid hydrolysis on ester groups of a polyzwitterion having the structural formula:
to form a polyzwitterionic acid having the structural formula:
Ordinarily, claims only include standard alphanumeric characters (i.e., plain text). However, there are numerous methods which rely on calculations which are best described in terms of mathematical equations. Such equations are allowed in the claims, however one must be careful to always define all variables and operations used in the claims, otherwise an “indefiniteness” rejection will be likely, under
35 U.S.C. § 112(b). An example is given below. Note that this is written as a “
Beauregard claim”, which is the proper way to write a software-implemented method (see § 2.08):
- A computer software product that includes a non-transitory computer readable storage medium readable by a processor, the non-transitory computer readable storage medium having stored thereon a set of instructions for Kalman filter state estimation in bilinear systems, the instructions comprising:
(a) a first sequence of instructions which, when executed by the processor, causes the processor to generate an observer for estimating a state vector xk associated with a bilinear system, the observer defining a covariance matrix Pk statistically relating the state vector xk, where k represents an integer time increment, the bilinear system being defined by xk+1 = Axk + B(xk ⊗ xk) + wk where A is a transition matrix defined by the bilinear system, B is a measurement matrix defined by parameters of the bilinear system, and wk is system noise at time k;
(b) a second sequence of instructions which, when executed by the processor, causes the processor to receive sensor data yk from a sensor, the sensor data being associated with the state vector xk as yk = Cxk + vk, where C is a measurement matrix defined by the parameters of the bilinear system and vk is measurement noise at time k …
