Southwall Technologies, Inc. v. Cardinal IG Co.

• Decision Date: 10 May 1995
• Docket Number: No. 94-1243,94-1243
• Parties: SOUTHWALL TECHNOLOGIES, INC., Plaintiff-Appellant, v. CARDINAL IG COMPANY, Defendant-Appellee.
• Court: U.S. Court of Appeals — Federal Circuit

Page 1570

54 F.3d 1570

34 U.S.P.Q.2d 1673

SOUTHWALL TECHNOLOGIES, INC., Plaintiff-Appellant, v. CARDINAL IG COMPANY, Defendant-Appellee.

No. 94-1243.

United States Court of Appeals Federal Circuit.

May 10, 1995.

Rehearing Denied; Suggestion for Rehearing

In Banc Declined

June 21, 1995.

Noemi C. Espinosa, Brobeck, Phleger & Harrison, of Palo Alto, CA, argued for plaintiff-appellant. With him on brief were William L. Anthony, Jr. and Douglas C. Rawles. Of counsel was Luther Kent Orton.

V. Bryan Medlock, Jr., Richards, Medlock & Andrews, of Dallas, TX, argued for defendant-appellee. With him on brief was Paul V. Storm.

Before MICHEL, LOURIE and BRYSON, Circuit Judges.

MICHEL, Circuit Judge.

Southwall Technologies, Inc. (Southwall) appeals the March 2, 1994 decision of the United States District Court for the Northern District of California, Docket No. C-92-0327-DLJ, granting summary judgment for Cardinal IG Company (Cardinal) that Cardinal's LOE ² window glazing product cannot infringe Southwall's Reexamined U.S. Patent No. B1 4,799,745 (the '745 patent). Because the district court as a matter of law correctly interpreted the claims of the '745 patent to foreclose literal infringement and correctly concluded that, as limited by prosecution history, the range of permissible equivalents precluded infringement under the doctrine of equivalents, we affirm.

BACKGROUND

The invention of the '745 patent is an improved heat mirror, a thin, transparent coating applied to glass or plastic that allows visible light to pass through but reflects heat (infrared light). Such coatings are useful as window glazing materials. A heat mirror generally comprises one or more thin layers of silver, which are transparent to visible light but reflect heat, spaced apart by a layer of dielectric material, typically metal oxide, an anti-reflective, non-absorbing material that decreases the reflection and increases the transmission of visible light. Two silver layers spaced apart by a dielectric layer form a Fabry-Perot interference filter. The heat mirror may also include additional layers of dielectric or other materials due to manufacturing constraints.

The specification of the '745 patent describes the invention as an improvement over the heat mirror of the Apfel patent, U.S. Patent No. 3,682,528. The Apfel patent teaches that to obtain thin, optically suitable layers of silver, it is necessary to first lay down a thin "nucleation" layer of nickel and then apply the silver over the nickel by vacuum deposition methods. Apfel further teaches that the silver layer may be coated with a thin layer of vapor-deposited nickel (a post-coat layer) to improve the durability of the heat mirror if another layer, such as a dielectric layer, is to be applied over the silver layer. Apfel's nucleation and post-coat layers may be a clear dielectric material such as titanium oxide rather than nickel. Because the nucleation and post-coat layers are time consuming and expensive to produce, an objective of Southwall's invention was to provide a Fabry-Perot filter with minimal complexity and production steps. The invention of the '745 patent accomplishes this objective by "employing as the interference filter a multilayer stack including at least two separate discrete continuous sputter-deposited transparent metal layers separated from one another by discrete continuous layers of dielectric." U.S. Pat. No. 4,799,745, col. 2, lines 21-25.

Claim 14 of the reexamined ¹ '745 patent, asserted by Southwall, recites (emphasis added): ² A visually transparent, infrared reflecting composite film comprising a transparent support having adhered to one surface thereof an interference filter having a plurality of continuous directly contiguous stacked layers, said layers comprising:

a. a dielectric layer,

b. [a] discrete sputter-deposited transparent metal layer,

c. one or more pairs of layers, each pair comprising a dielectric spacer layer and a discrete sputter-deposited transparent metal layer, and

d. a dielectric outer layer,

wherein the dielectric is a sputter-deposited dielectric; the metal layers each comprise silver and each are from 4 to 17 nm in thickness and the dielectric layers each have an index of refraction of from about 1.75 to about 2.25 with the spacer layers having a thickness of from 70 to 100 nm and outer layers having a thickness of from about 30 nm to about 70 nm.

In other words, claim 14 recites a support, such as glass or plastic, which is coated with "continuous directly contiguous stacked layers" of sputter-deposited ³ dielectric, silver, sputter-deposited dielectric, silver and, finally, sputter-deposited dielectric material. The '745 specification defines "directly contiguous" as having "its usual meaning of being in actual contact, i.e., of being adjoining." When the examiner nevertheless questioned the meaning of "directly contiguous" in a July 5, 1988 office action, Southwall replied:

The term "directly" as used in the claims is intended to mean that the layers are present or laid down contiguous with one another without intervening layers. In other words, no nucleation layers are present between two "directly contiguous" layers or between layers which are laid down "directly" on one another.

In accordance with Southwall's own definition, unlike the interference filter disclosed in the Apfel patent, the interference filter recited in claim 14 can have no additional layers between the silver and the sputter-deposited dielectric layers, not even nucleation or sacrificial barrier layers.

Cardinal's LOE ² product consists of the following layers on a glass support: zinc oxide (a dielectric), silver, titanium oxide (a dielectric), zinc oxide, silver, titanium oxide, zinc oxide, titanium dioxide and a final zinc oxide layer. The titanium oxide layer is formed by a two-step process in which titanium metal is first sputtered in a nonreactive argon atmosphere to form a layer of titanium metal covering the silver layer. The zinc oxide layer is formed by a reactive sputtering process involving the sputtering of zinc metal in an oxygen atmosphere. Sputtered zinc metal reacts with the oxygen to form zinc oxide which is deposited directly onto the surface. During this process the layer of titanium metal already there is converted to titanium oxide by the action of oxygen. ⁴ The titanium metal layer acts as a "sacrificial barrier layer" by protecting the silver layer from oxidation during formation of the zinc oxide dielectric layer. ⁵ For purposes of summary judgment analysis, we assume it is completely converted to titanium oxide during this step. In sum, Cardinal's zinc oxide layer is formed by a one-step reactive sputtering process in which zinc oxide is directly deposited, whereas its titanium oxide layer is formed by a two-step process wherein the first step requires deposition of titanium metal and the second step requires oxidation of titanium metal to create titanium oxide.

Southwall filed the present suit on January 14, 1992 alleging that Cardinal's LOE ² heat mirror infringes the '745 patent. Cardinal moved for summary judgment on the grounds that (1) its product does not infringe the '745 patent, (2) the '745 patent is invalid We have jurisdiction over this patent infringement action pursuant to 28 U.S.C. Sec. 1295 (1988).

for failure to state the best mode of the invention, and (3) the '745 patent is invalid as either anticipated by or obvious in light of the prior art. The district court granted Cardinal's summary judgment motion on the first ground but denied it on the other two. Southwall appeals the ruling that Cardinal does not infringe the '745 patent, either literally or under the doctrine of equivalents.

DISCUSSION

Summary judgment is appropriate only "if the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any material fact and that the moving party is entitled to judgment as a matter of law." Fed.R.Civ.P. 56(c). The evidence must be viewed in the light most favorable to the nonmoving party. SRI Int'l v. Matsushita Elec. Corp. of Am., 775 F.2d 1107, 1116, 227 USPQ 577, 581 (Fed.Cir.1985) (in banc). Regardless of the nature of the issue determined favorably to the movant, we review the district court's grant of summary judgment de novo. International Visual Corp. v. Crown Metal Mfg. Co., 991 F.2d 768, 770, 26 USPQ2d 1588, 1590 (Fed.Cir.1993).

I. Literal Infringement

A literal infringement analysis requires two separate steps. First, the asserted claims must be interpreted by the court as a matter of law to determine their meaning and scope. Markman v. Westview, Instruments Inc., 52 F.3d 967, 979 (Fed.Cir.1995) (in banc); Senmed, Inc. v. Richard-Allan Med. Indus., Inc., 888 F.2d 815, 818, 12 USPQ2d 1508, 1511 (Fed.Cir.1989). In the second step, the trier of fact determines whether the claims as thus construed read on the accused product. Id., 12 USPQ2d at 1511. To establish literal infringement, every limitation set forth in a claim must be found in an accused product, exactly. Becton Dickinson & Co. v. C.R. Bard, Inc., 922 F.2d 792, 796, 17 USPQ2d 1097, 1099 (Fed.Cir.1990). Infringement, both literal and under the doctrine of equivalents, is an issue of fact. SSIH Equip. S.A. v. United States Int'l Trade Comm'n, 718 F.2d 365, 376, 218 USPQ 678, 688 (Fed.Cir.1983).

The parties agree that a genuine issue of fact as to whether Cardinal's product literally infringes the '745 patent exists only if Cardinal's titanium oxide and zinc oxide layers together form "a sputter-deposited dielectric" layer. Because Cardinal does not dispute that the zinc oxide is "a sputter-deposited dielectric," the key issue here becomes whether the titanium oxide covering the silver can also be described as "sputter-deposited" as that phrase is used in claim 14 and elsewhere defined in the '745 patent. If Cardinal's titanium oxide...