SRI INTERN. v. Matsushita Elec. Corp. of America
| Decision Date | 23 July 1984 |
| Docket Number | No. C-82-3625-WWS.,C-82-3625-WWS. |
| Citation | 224 USPQ 70,591 F. Supp. 464 |
| Parties | SRI INTERNATIONAL, Plaintiff, v. MATSUSHITA ELECTRIC CORPORATION OF AMERICA, and Matsushita Electric Industrial Co., Ltd., Defendants. |
| Court | U.S. District Court — Northern District of California |
Edward B. Gregg, Willis E. Higgins, Gregg, Caplan & Higgins, Geoffrey A. Steel, Menlo Park, Cal., for plaintiff.
Morton Amster, Michael G. Berger, Anthony F. Locicero, Amster, Rothstein & Engelberg, New York City, Jay M. Spears, Howard, Rice, Nemerovski, Canady, Robertson & Falk, San Francisco, Cal., for defendants.
Plaintiff SRI International ("SRI") brings this action against defendants Matsushita Electric Co., Ltd., and its subsidiary, Matsushita Corporation of America, (collectively "MEI") for infringement of its U.S. Patent No. 3,379,633 ("the '633 patent"), originally issued to Albert Macovski in 1968, for a single tube color television camera.1 Plaintiff claims that since 1978 MEI has been engaged in the manufacture and sale in the United States of single tube color television cameras which infringe Claims 1, 2, 7, 8, 9, and 10 of its '633 patent, and it seeks treble damages.2 Defendants answer that the camera they sell does not infringe the asserted claims and that the '633 patent is invalid under 35 U.S.C. § 103 because its allegedly novel feature would have been obvious at the time of issuance to those of ordinary skill in the art. At the pre-trial conference held before the Court on April 13, 1984, defendants moved for summary judgment, claiming that plaintiff's submissions failed to raise a genuine issue of material fact as to infringement or obviousness. Having considered both parties' memoranda with regard to the summary judgment motion as well as the evidence the parties proposed to introduce at trial, the Court concludes that as a matter of law the accused device does not infringe the '633 patent and that defendants are entitled to summary judgment.
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.
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 frequency 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.
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 representing 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 which 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.
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 geometry, 1.4 centimeters.
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.
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...
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SRI Intern. v. Matsushita Elec. Corp. of America
...the Northern District of California granting summary judgment of non-infringement to Matshushita Electric Corporation (MEI). 591 F.Supp. 464, 224 USPQ 70 (1984). We Familiarity with the district court's opinion being assumed, only those factors necessary to an understanding of this court's ......