join, dissenting.
I disagree with the lead opinion to reverse the district court’s grant of summary judgment of noninfringement. The claims asserted by SRI, interpreted in view of the ‘633 patent specification, file history and prior art, are not infringed by the MEI device.1 As a separate and independent *1133basis for finding noninfringement, I believe that under the reverse doctrine of equivalents, the MEI device does not infringe SRI’s asserted claims.
The lead opinion starts on the first page in its BACKGROUND section with this statement:
The district court’s opinion contains an excellent explication of the technology-involved, reflecting a clear recognition of the undisputed fact that the filter and camera embodiment described in the specification of SRI’s United States Patent No. 3,378,633 (the ’633 patent) issued ... April 16, 1968, operate somewhat differently from the MEI filter and camera accused of infringement. (Emphasis as in lead opinion).
Since there is disagreement in this case whether material facts are in dispute, instead of just referring to the district court opinion and merely stating that it contains an “excellent explication of the technology involved,” I choose to quote the undisputed facts as found by the district court. It is significant that the lead opinion in its opening paragraph recognizes the “undisputed fact that the filter and camera embodiment described in the specification of SRI’s United States Patent No. 3,378,633 (the ’633 patent) issued ... April 16, 1968, operate somewhat differently” from the MEI filter and camera accused of infringement. The trial judge chose to find the undisputed material facts to be as follows:
“FACTS
“The ’633 patent describes a method by which single tube color television cameras can perceive and transmit color images. Although the detailed technology of the patented and accused devices is complex, the gist of the ’633 patent and its only teaching at issue in this action is the way in which a special light filter employs geometric principles to register the color of an object being televised. To understand how the filter facilitates color transmission, however, it is helpful to briefly note the functioning of the camera itself.
“1. Background
“Single tube television cameras operate by focusing the image to be televised onto a photosensitive image area in a part of the camera called a pick-up tube. The pick-up tube converts the image into a series of electrical signals by means of a sequence (or ‘raster’) of horizontal lines across the image area. The amplitude of the electrical signals varies according to the intensity of light at any given point on the image area. These signals are then transmitted to a receiver and used to reproduce, the original image on a television screen. When generated directly from the pick-up tube, the signals can record the intensity of the image but not its color.
“An image in color is made up of various light components: a general brightness component called ‘luminance,’ and components of each of the three primary colors: red, blue, and green. To reproduce an image in color, the pick-up tube of a television camera must subdivide the image area into three primary color areas so that electrical signals corresponding to each of these colors can be generated simultaneously by a single raster scan of the pickup image area.
“Both systems at issue in this action accomplish color subdivision by placing a composite filter in front of the pick-up tube. The composite filter consists of two super-imposed filters each with a grid of different colored stripes. The stripes of one grid are yellow, a color that passes all light except blue (and is referred to as ‘subtractive blue’), and the other’s stripes are cyan, a color that passes all light except red (and is referred to as ‘subtractive red’). As the scanning beam moves across the image over which the composite filter has been placed, the output signal generated includes two signal components representing the red and blue portions of the image. If the yellow stripes are of a different width than the cyan stripes, the beam of light moving at a constant speed will generate output signals of different *1134frequency for the light (i.e. colors) passing the yellow stripes than for that passing the cyan stripes. These output signals, which are said to have ‘encoded’ the color information from the image, are then ‘decoded’ by a series of electrical filters and ultimately used to reproduce the image on a television screen.
“2. Prior Art: The Kell Patent
“The way in which striped filters ‘encode’ color information is further explained by reference to U.S. Patent No. 2,733,291, issued in 1956 to Ray Kell for a color television camera (‘the Kell Patent’), which both parties concede to be the most analogous prior art.
“Kell teaches the use of a composite filter consisting of two grids of stripes, one colored cyan and the other yellow as shown in Figure # 1:
The stripes on the two grids vary in width so that all the yellow stripes, of uniform width, are either wider or narrower than the cyan stripes, also of uniform width. As the scanning beam moves across the image area covered by the composite filter, the blue light component of the image is periodically interrupted when the beam passes over each yellow stripe. This periodic interruption generates an electrical signal rerpresenting the blue content of the image at a frequency corresponding to the frequency with which yellow (subtractive blue) appears in front of the image area. At the same time the filter generates a signal representing the red content of the image at a frequency corresponding to the frequency of cyan (subtractive red) stripes.
“Under the Kell patent, because the cyan and yellow stripes vary in width, the frequency of the red and blue signals differ from each other and from the frequency of the luminance or general brightness component. Thus if the filter has more yellow stripes than cyan stripes, the frequency of the three light components can be diagrammed as appears in Figure # 2
where the horizontal axis represents frequency measured in megahertz (MHz) and the vertical axis represents amplitude or intensity of the light. Each color is said to have a ‘carrier frequency’ at the central hump of its frequency range and ‘side bands’ on either side of the carrier frequency. As can be seen, the luminance component has the lowest frequency range while the red and blue components have higher frequency ranges depending on the spacing of the subtractive color grids.
“The output signals thus generated are then ‘decoded’ by three electrical filters called ‘low pass’ and ‘band pass’ filters *1135which are able to separate out luminance, red, and blue signals by virtue of the variations in their carrier frequencies: In a process not relevant to this action, the green color component is obtained by subtracting out the blue and red components from the luminance component. The separated signals are then funnelled out through different output channels and are ultimately recombined to reproduce the colored image by means of a second scanning beam projected on the television screen.
“The Kell patent suggests a number of minor variations to this basic scheme, one of which is relevant to this action. Kell recognized that the superimposition of one vertical grid on another creates the possibility of ‘beats’ or ‘moire’ interference which takes the form of light and dark bands across the filter. The Kell patent teaches that moire interference can be reduced if the stripes are placed at an angle, rather than parallel, to one another. Figure 4D of the Kell patent shows striped grids so angled, and the specification explains that:
the orientation of the different negative grids with respect to the scanning direction as shown in Figure 4D decreases any moire effects that might otherwise be produced.
“3. The ’633 Patent
“Plaintiff’s ’633 patent teaches basically the same system as Kell except that the two grids have stripes of equal width. The grids are placed at an angle to one another, however, so that as the scanning beam moves horizontally across the filter, the frequency ranges of the red and blue components will still differ. As shown in Figure # 3, the scanning beam moves across a yellow grid of 1 centimeter-wide stripes placed vertically on the pick-up tube.
In Figure # 4, it moves across a cyan grid of stripes also 1 centimeter wide but placed at a 45° angle to the vertical; the resulting distance traveled by the beam over each cyan stripe is, as a matter of Pythagorean geomety, 1.4 centimeters.
*1136
The frequency range generated by the second grid for the red signal component would thus be lower than the frequency range generated by the first grid for the blue signal component. The frequency diagram for the ’633 patent is thus identical to that of the Kell system in Figure # 2, and the signals are decoded by low- and bandpass filters just as in Kell.
“4. The MEI System
“The MEI camera also employs a composite filter of angled cyan and yellow striped grids with equally spaced stripes to encode color signals off a single pick-up tube. The grids of the MEI filter, however, are placed at equal and opposite angles to the vertical. As a result, the distance travelled by the scanning beam over the stripes of both grids is the same and no variation in frequency range is created between the blue and red components. The appearance of the frequency diagram is shown in Figure # 5:
“Because the MEI filter does not generate the frequency range variation between red and blue signal components based on stripe widths that vary in relation to the scanning movement, as taught by the Kell and ’633 patents, the camera cannot decode the color components by means of bandpass filters. Instead, it employs what is called a 1-H delay line comb filter which separates the red and blue components by means of a complicated series of manipulations as follows. As the scanning beam moves across the first scan line over the filtered image, it creates signals of alternating red and blue zones as shown in Figure # 6:
*1137Figura #6
These signals are said to be ‘out of phase’ because the red and blue components alternate rather than overlap. As the beam moves across the next line, however, it creates a signal of zones containing neither color alternating with zones containing both colors. Here the red and blue components are ‘in phase’ because they overlap rather than alternate. The 1-H delay line comb filter operates to delay the scan line signal just long enough for the filter to align it with the next scan line and then combine the two. Where the red signals in a given pair of aligned zones from two scan lines are in phase once the scan lines have been shifted and combined, and the blue signals are out of phase, the blue signals will cancel out and only the red will remain. Conversely, where the blue signals are in phase and the red out of phase, only the blue signal will remain. Thus the 1-H delay line comb filter uses the phase variation of the red and blue signals in alternating scan lines to separate out or decode the two colors. The luminance and green components are separated out in the same way as in the Kell and ’633 patents, and the various signals recombined to reproduce the full color image on a television screen.”
The lead opinion does not dispute any of the facts recited in the above trial judge’s findings. In fact, it agrees that they were the facts. As I see it, then, the major weakness of the lead opinion lies in its failure to point, with convincing or useful specificity, to any material facts in dispute.
While recognizing that summary judgment is granted when there is no genuine issue of material fact, Fed.R.Civ.P. 56, the lead opinion asserts that MEI did not carry the burden required by the rule to establish the absence of a material fact issue in regard to the manner of operation of its device. I am at a loss, however, to determine from the lead opinion, an issue of material fact, supported by the record below, which precludes the court’s grant of summary judgment. See Barmag Barmer Maschinenfabrik AG v. Murata Machinery, Ltd. 731 F.2d 831, 836, 221 USPQ 561, 564 (Fed.Cir.1984) (party opposing motion for summary judgment must point to evi-dentiary conflict created on the record; mere conclusory statements are insufficient). Suggestions by the lead opinion that evidence may be developed at trial is mere speculation and inappropriate in ruling on a Rule 56 motion. First National Bank v. Cities Service, 391 U.S. 253, 289, 88 S.Ct. 1575, 1592-93, 20 L.Ed.2d 569 (1968).
Furthermore, where, as here, the evidence on an issue leaves no room for any reasonable difference of opinion as to its resolution, the district court should resolve such issue, as it did in this case, as a matter of law. See Jamesbury Corp. v. Litton Industrial Products, Inc., 756 F.2d 1556, 1560, 225 USPQ 253, 257 (Fed.Cir.1985); Williams v. Butler, 746 F.2d 431, 440 (8th Cir.1984); Trace X. Chemical v. Canadian Industries, 738 F.2d 261, 265 (8th Cir.1984), cert. denied, — U.S.-, 105 S.Ct. 911, 83 L.Ed.2d 925; B.D. Click Co., Inc. v. United States, 614 F.2d 748, 755, 222 Ct.Cl. 290, 303 (1980); Admiral Theatre Corp. v. Douglas Theatre Co., 585 F.2d 877, 893 (8th Cir.1978), Simmonds Precision Products, Inc. v. United States, 546 F.2d 886, 891, 212 Ct.Cl. 305, 315 (1976), Gillette Diary, Inc. v. Hydrotex Industries, Inc., 440 F.2d 969, 971 (8th Cir.1971), Sherwin v. U.S., 436 F.2d 992, 1002, 193 Ct.Cl. 962, 979 (1971).
*1138I agree with the district court that the attempt to characterize the MEI camera as a “frequency” device rather than a “phase” device, hardly rises to the level of an evi-dentiary conflict as to the nature and operation of the accused product sufficient to preclude a grant of summary judgment. While it is true that frequency and phase are not synonymous terms, the court below is quite right in its conclusion that the application of one label rather than another does not detract from the fundamental distinction between MEI’s use of a single frequency modulated carrier in its operation and SRI’s use of a two frequency modulated carrier in the ’633 patent.2
Since there was no dispute as to the manner in which the accused device operated, the district court correctly concluded that the question of infringement reduced to a construction of the scope of the claims asserted by SRI. This, of course, is a question of law. SSIH Equipment, S.A. v. U.S. International Trade Commission, 718 F.2d 365, 218 USPQ 678 (Fed.Cir.1983). The district court particularly considered the history of prosecution of SRI’s ’633 patent before the Patent and Trademark Office (PTO) and properly concluded that SRI, having argued a construction of the claims which emphasized the generation of frequency variation by angle differentiation, was precluded from arguing a construction which involves essentially no frequency variation for the purposes of infringement.
The lead opinion on this point takes the position that the district court misconstrued the nature and effect of the prosecution history and that, in essence, if SRI had relied for patentability over the Kell patent on the basis of the generation of two frequencies in a single pass of the scanning beam across light passing through the composite grid filter, the examiner would necessarily have rejected the claims as based on an admittedly old feature. In support, the lead opinion states that SRI never discussed in its Remarks to the PTO, a composite filter that generated only one modulating frequency and that SRI acknowledged that Kell generated two.
As I view it, during the prosecution of '633 patent, the principal argument made to distinguish the claimed invention from the Kell patent, the closest prior art, was SRI’s contention that the Macovski filter “insures two different modulating frequencies by virtue of placing one grid at an angle to another grid,” while Kell generated two different modulating frequencies by making “his line density different for each grid.” This point is perhaps best illustrated by quoting, as does the lead opinion, from Remarks filed by SRI in response to the examiner’s initial rejection of certain claims in view of Kell:
Claim 1, as amended, distinguishes over Kell in calling for a spatial filter which is comprised of a first grid of parallel spaced lines having the color of a subtractive primary, and a second grid which is relatively angularly superimposed over all of said first grid, said second grid having parallel spaced lines which are the color of another subtractive primary____ Claim 1 further distinguishes over Kell in calling for each *1139grid to have the same line density. Every teaching in Kell, both in the specification and in the drawings, ... is that the line density is different for each grid. [Emphasis in original.]
The reason why Kell makes his line density different for each grid is that that is the way that he generates his two different modulating frequencies. This applicant insures two different modulating frequencies by virtue of placing one grid at an angle to another grid. As a result, the scanning beam, which traverses the line grids in successive parallel lines, is interrupted at two different frequencies by the two angularly disposed lines of the two grids.
The lead opinion is correct in noting that Macovski did not distinguish his own invention from Kell on the basis of Kell generating only one frequency in a single scan pass. There would be no reason to do so, of course, as Kell generated two modulating frequencies in a single scan pass and relied on such frequency variation to produce color information. Kell produced this frequency variation using unequal line densities in two separate grids of a filter. The ’633 patent, in contrast, using equal line density grids, relies on a particular angular orientation of these grids to produce frequency variation. To avoid Kell, and yet produce the same color information, Macovski distinguished his invention on the basis of angular orientation of these grids, in contrast to their unequal line density as in Kell.
The lead opinion further concludes that SRI’s Remarks to the PTO can only be applied in a structural, not operational context. I cannot agree. Having made narrowing arguments to the PTO to obtain allowance of a patent, SRI may not now seek a broader scope for its patent claims in an attempt to cover the MEI device. Moreover, arguments made to the PTO to define and explain the claimed invention for the purpose of distinguishing it from the prior art limit the proper interpretation of the claim language, whether or not actual amendments to the claim language are
made and whether or not the lead opinion chooses to classify such arguments as “structural” or “operational” in nature. Coleco Industries, Inc. v. U.S. International Trade Commission, 573 F.2d 1247, 197 USPQ 472 (CCPA 1978). As stated by the Court of Customs and Patent Appeals in Coleco:
A response to an examiner’s office action may include an amendment accompanied by remarks or it may include only remarks. Because applicant’s ultimate goal in submitting amendments and offering arguments in support thereof is the securing of a patent, we find no reason not to extend the traditional es-toppel doctrine beyond estoppel by amendment to estoppel by admission.
573 F.2d at 1258, 197 USPQ at 480.
I add further on this point, that the lead opinion, in concluding that SRI could not have properly relied for patentability over Kell on the basis of the generation of two different frequencies in a single scan pass across the composite grid filter is outside its rightful purview. Since the district court did not rule on the validity of the ’633 patent, this Court may not attempt to circumscribe any future resolution of that issue. See Structural Rubber Products v. Park Rubber, 749 F.2d 707, 223 USPQ 1264 (Fed.Cir.1984).
In a related holding, the lead opinion concludes that the district court, in interpreting the asserted claims in light of the specification, improperly read limitations into them from other claims and in so doing, erred as a matter of law. I take a different position.
It is axiomatic that claims of a patent must always be interpreted in light of the specification. Autogiro Company of America v. United States, 384 F.2d 391, 181 Ct.Cl. 55, 155 USPQ 697 (1967). This is not to say, of course, as the lead opinion correctly notes, that an applicant in his specification must describe every conceivable and possible future embodiment of his invention. Raytheon Co. v. Roper Corp., 724 F.2d 951, 957, 220 USPQ 592, 597 (Fed.Cir.1983). But where, as here, the specifi*1140cation does not refer to an angular orientation of the grids of the filter as only a “best mode” for utilizing the invention, but rather teaches this arrangement as essential to achieve the objects of the invention, I am satisfied, as was the trial judge, that the invention has not been improperly limited.
In this case, the specification of the ’633 patent teaches that the angles and orientation of the two grids of the filter are chosen so as to produce adequate separation between the blue and red frequency components of the modulated carrier. The specification provides no other basis for selecting the angle or orientation of the filter’s grids. SRI’s argument that the phrase “relatively angularly superimposed”, appearing in its asserted claims should be read to mean merely that the grids of the filter must be crossed at any angle, was properly rejected by the lower court which inspected the specification of the ’633 patent and concluded in light thereof, that the grids of the filter must be angled to generate frequency variation for red and blue color signals. Nevertheless, the lower court’s correct interpretation of the claims in light of the specification is mischaracter-ized in the lead opinion as an improper exercise whereby the limitations of narrow claims are read into broader claims.
Finally, I believe that the district court properly held that the MEI device “cannot be found to do the same work in the same way” as the device claimed in the ’633 patent. Considered as a whole, the record shows that the MEI device operates in a fundamentally different way from the SRI filter, produces a different electrical signal and requires entirely different signal processing. That the two devices ultimately produce an image should not obscure the fact of how each accomplishes this result since numerous devices which could never reasonably be argued to be equivalents also produce images. Under these circumstances, according to the reverse doctrine of equivalents, the MEI device cannot be found to infringe. Westinghouse v. Boyden Power Brake Co., 170 U.S. 537, 18 S.Ct. 707, 42 L.Ed. 1136 (1898). Leesona v. U.S., 530 F.2d 896, 906, 208 Ct.Cl. 871 (1976) (“more than a literal response to the terms of the claims must be shown to make out a case of infringement.”) Since the question of infringement in this ease is resolved on an undisputed fact record, the application of the reverse doctrine of equivalents is a matter of law. Kalman v. Kimberly Clark Corp., 713 F.2d 760, 218 USPQ 781 (Fed.Cir.1983); see also Sanitary Refrigerator Co. v. Winters, 280 U.S. 30, 36, 50 S.Ct. 9, 10-11, 74 L.Ed. 147 (1929) (“upon the undisputed evidence the question of infringement resolves itself ... into one of law, depending upon a comparison between the structure disclosed on the face of the patent and the [accused device] ... and the correct application thereto of the rule of equivalency.”)
I dissent lastly from the lead opinion statement of reasons for in banc action. This case was not taken in banc to exclusively consider overruling Kalman. Rather, in addition to the Kalman issue, the in banc action was taken to determine whether summary judgment was improperly granted by the lower court and whether the lower court impermissably denied SRI a jury trial.
Based on the foregoing, I would affirm the decision of the district court.
In view of the disposition of the case as suggested herein, notwithstanding the fact that there has been no clear and definitive ruling by the district court denying a request for a jury trial, see Ashwander v. Tennessee Valley Authority, 297 U.S. 288, 346-47, 50 S.Ct. 466, 482-83, 80 L.Ed. 688 (1936), I believe it unnecessary to go into the question of the right to a jury trial in complex cases. The Third Circuit has stated that, in exceptional circumstances, the right to jury trial may be denied due to the “complexity” of the suit, see In re Japanese Elec. Prod. Antitrust Litigation, 631 F.2d 1069 (3rd Cir.1980), while the Ninth Circuit has rejected such a “complexity” exception in In re U.S. Financial Securities Litigation, 609 F.2d 411, 432 (9th Cir.1979), cert. denied, 446 U.S. 929, 100 S.Ct. *11411866, 64 L.Ed.2d 281 (1980). The lead opinion in an addendum takes the Ninth Circuit views. It is a complicated question of Constitutional law, mooted in this case by the disposition I suggest.
. “Literal correspondence,” as the lead opinion coins the term, is quite different from literal infringement under the precedent of this Court. Under our precedent, literal infringement cannot be determined without first determining what a claim means in light of the specification, the prosecution history, and the prior art. Envirotech Corp. v. Al George, Inc., 730 F.2d 753, 760, 221 USPQ 473, 477 (Fed.Cir.1984); SSIH Equipment S.A. v. USITC, 718 F.2d 365, 376, 218 USPQ 678, 688 (Fed.Cir. 1983); Astra-Sjuco, A.B. v. USITC, 629 F.2d 682, 686 (CCPA 1980); Autogiro Co. of America v. United States, 384 F.2d 391, 396-97, 181 Ct.Cl. 55, 155 USPQ 697, 702 (1967). The lead opinion, in contrast, uses the term “literal correspondence" to mean that the words of a claim are to be read in a vacuum, *1133irrespective of specification, prosecution history or prior art. MEI has never conceded literal infringement in this case. Rather, MEI has argued that there was no literal infringement of properly interpreted claims.
. I have considered the Ball affidavit but fail to understand how the experiments of Mr. Ball raise an issue of material fact when, on the undisputed record, the SRI and MEI cameras do not operate in substantially the same way. Graver Tank & Manufacturing Co. v. Linde Air Co., 339 U.S. 605, 70 S.Ct. 854, 94 L.Ed. 1097, 85 USPQ 328 (1950). The Nakabe paper, referred to in the lead opinion on page 12 is even less convincing to show material facts in dispute. SRI asserts in this context, that Nakabe describes the MEI camera as a "single carrier-frequency division system” while describing a camera system such as that described in the '633 patent, as a “two carrier-frequency division system". The mere use of the term "frequency”, however, does not compel the result that the MEI system operates as a so-called "frequency" system. On the contrary, as the trial judge realized, the term "single carrier-frequency division system” simply means that the MEI system modulates a carrier wave with only one “single” modulating frequency. The term “two carrier frequency division system” as applied to the '633 patent only means that, in the system disclosed by the patent, a carrier wave is modulated with "two” modulating frequencies. The findings of the trial judge are in accord with Nakabe’s descriptions.