Opinion ID: 772056
Heading Depth: 2
Heading Rank: 1

Heading: The Oyama '532 Patent

Text: 4 In the late 1980s, Takuji Oyama was a scientist employed by Asahi. Together with co-workers Koichi Suzuki and Mamoru Mimhashi, he was named as an inventor in a patent application filed on November 25, 1987, which eventually matured into U.S. Patent No. 4,859,532 (the '532 patent). The application is directed to a coating having multiple thin layers of silver, interspersed by layers of metal oxides, such as zinc oxide. By alternating layers of silver with layers of metal oxides, Oyama disclosed that the silver would become increasingly reflective of radiant heat without sacrificing its transparency to visible light. The following diagram, adapted from Cardinal's brief, illustrates the claimed coating: 5 [Tabular or Graphical Material Omitted] 6 In the written description of the patent application, Oyama recited that interlayers could be laid between the silver and metal oxide layers. Oyama disclosed that these interlayers, which are sufficiently thin to avoid substantially changing the optical properties of the silver and metal oxide layers, serve the purpose of rendering the layers more durable and increasing their adhesivity. The relevant part of the written description states: 7 For the purpose of improving the adhesion or durability of the coating layers, an interlayer having a thickness not to substantially affect the optical properties may be inserted at the interface with the substrate or at the interface between adjacent layers or at the interface with air. 8 '532 patent, col. 4, ll. 63-68. Oyama's application provides eight examples of low-emissivity coatings. None of these examples recite the use of interlayers. 9 Oyama's initial application contained five claims. Claim 4 of the application, which was allowed without amendment, issued as claim 1 of the '532 patent. Claim 1 of the '532 patent recites a coating composed of five alternating layers of zinc oxide (ZnO) and silver (Ag), with no reference to interlayers. The claim, in full, reads: 10 1. A transparent laminated product comprising a transparent substrate and a 5-layered transparent coating composed of a first ZnO layer formed on the substrate, a second Ag layer formed on the first layer, a third ZnO layer formed on the second layer, a fourth Ag layer formed on the third layer and a fifth ZnO layer formed on the fourth layer, and having a visible ray transmission of at least 60%, wherein the thickness of each Ag layer is from 60 to 250. 11 Oyama cancelled the four other claims of his application after they were twice rejected by the PTO examiner. The cancelled claims, like issued claim 1, disclosed a coating composed of multiple metallic layers, but recited the use of a transparent oxide rather than specifying the use of zinc oxide. The examiner rejected these broader claims in light of the prior art. 12 AFG and Asahi are joint owners by assignment of the '532 patent.