In re Langdon

77 F.2d 920, 22 C.C.P.A. 1245, 1935 CCPA LEXIS 178
CourtCourt of Customs and Patent Appeals
DecidedJune 3, 1935
DocketNo. 3490
StatusPublished
Cited by6 cases

This text of 77 F.2d 920 (In re Langdon) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
In re Langdon, 77 F.2d 920, 22 C.C.P.A. 1245, 1935 CCPA LEXIS 178 (ccpa 1935).

Opinion

GRAi-iam, Presiding Judge,

delivered the opinion of the court:

An application, was filed in the United States Patent Office by appellant, for a patent upon certain claimed new and useful improvements in metal protected mirrors. As a result of the proceedings in the office, claims 3 to 16, inclusive, and claims 27 to 33, inclusive, were rejected by the examiner. On appeal, the Board of Appeals reversed the examiner as to claims 15 and 16, and affirmed his decision as to all other claims. Claims 3,4, 9, and 14 are thought to be typical, and are as follows:

3. A mirror comprising a body of light-transmitting medium, an opaque relatively thin reflective silver film adherent to one surface of said body, a metallic protective coating metallically united to said silver film, the metal in said protective coating being chosen from a group in the periodic system separated from the group containing silver by at least three other groups and excepting nickel.
4. A stable reflecting light comprising in combination a heated source of light and a mirror exposed to the heat of said light, said mirror comprising a body of light-transmitting medium, an opaque relatively thin reflective silver film adherent to one surface of said body, a metallic protective coating metal-lically united to said silver film, the metal in said protective coating being one chosen from Group VIII of the periodic system.
9. A mirror comprising a body of light-transmitting medium, an opaque relatively thin reflective silver film adherent to one surface of said body, a metallic protective coating metallically united to said silver film, the metal in said protective coating, excepting nickel, being incapable of destroying the characteristic surface of silver under the conditions of normal exposure of said mirror, which conditions cause copper as a protective film to discolor or modify the reflecting surface of the silver film.
14. A stable reflective light comprising in combination a heated source of light and a mirror exposed to the heat of said light, said mirror comprising a body of light-transmitting medium, an opaque relatively thin reflective silver film adherent to one surface of said body, and a protective nickel coating metallically united to said silver film.

The subject matter of the invention is a mirror of glass, or other light transmitting medium, with a silver reflecting back coating, which silver .coating is backed by another coating of a metal not belonging to the same group of the periodic system as silver, and which will not produce a tarnish .or colored appearance in conjunc[1247]*1247tion with the silver coating, as a result of the application of heat or light to the surface of the reflector. This second coating is, in turn, covered by a protective coating of paint, or other like substance. The substance of the claimed invention is that the practice in-the prior art in the preparation of such mirrors has been to use a copper backing for the silver coat; that this copper backing, or backing of a similar metal of the same group or kind, will deteriorate by an admixture or alloying of the copper and silver coats; that the appellant has discovered why this discoloration takes place; that the same will not occur when a so-called “ white metal ” is used, or a metal which is in any of the groups from III to VIII of the periodic system. The appellant contends that his disclosure is new to the art and is inventive.

During the progress of the application through the Patent Office, the appellant, through his .counsel, amended his application by eliminating any claim for a backing of the metal nickel as a secondary coating for the mirror, doing so in view of a patent to Liebig (British) No. 1255, which appellant had discovered, and which he cited. The appellant, also, in the progress of his claims, filed a number of affidavits in which the commercial success of appellant’s product seems to be established.

The examiner cited two references as follows: Dake, 1,759,099, May 20, 1930, and Corbit 1,835,636, December 8, 1931, and rejected all the claims upon these references.

The Board of Appeals cited the same references relied upon by the examiner. In addition, the board recurred to the patent to Liebig. The board called attention to the fact that the appellant had attempted to distinguish his claims from those of the Liebig patent, by adding the words “ excepting nickel ” to each of the claims 3, 9, 10, 12, 13, 27, 28, and 29, and by prefixing each of claims 4, 5, 6, 8, 11, 14, and 15 with the statement, “ a stable reflecting light comprising in combination a heated source of light and a mirror exposed to the heat of said light,” or similar language.

As to the expression “ excepting nickel,” the board stated that this was a negative expression, “ whereas the distinguishing features should be-positively stated in the claims.”

As to the attempted differentiation from the Liebig reference as to a reflector adapted for use in proximity to- a source of light and-heat, the board was of opinion that the Liebig mirror was clearly adapted for use as a reflector in connection with a source of light and heat.

All the claims except 15 and 16 were further found to be properly rejectable oil features disclosed in the prior art. As to claim 15, which claims for a protective coating of iron, and 16, which recites [1248]*1248■ a protective coating of cobalt, these were thought to be fairly allowable.

The reference Dake discloses a process for manufacturing reflectors for headlights and the like. The patent discloses the use of silver and chromium as reflecting surfaces, and that silver easily tarnishes and loses its brilliancy; that it is necessary to interpose between the chromium reflecting surface and a backing of copper an intermediate layer of material, such as nickel, in a reflector. The patent also discloses that silver chemically deposited is always porous, and that it is impossible, in a chemical deposit of silver, to make it completely opaque; that in such cases it is necessary to back the silver up by another layer of silver put on by electroplating, upon -which may next be placed a layer of copper. This, the patentee recites, will keep the silver surface from tarnishing.

The patent to Corbit involves the making of surfaces plated with chromium used for reflecting purposes, and in which the plating of chromium is backed up by a foundation of metal which “ also has reflecting properties and color similar to that of chromium.” This undercoating, the patent recites, should be one, “ the electrolytic potential of which is intermediate chromium and copper.” These reflectors are used for lighting devices which are subject to “ rather high temperatures.” The patent recites that the backing coat of the chromium should be a metal “ similar in color to chromium.” Nickel or cadmium is suggested as a backing coat, which, it is stated, “ serves as a silver-like backing for the chromium in case the chromium plating is thin or becomes worn through.”

The patent to Liebig is one dealing with silvered surfaces of mirrors and other glass articles, and proposes to protect the silvered surfaces of mirrors and other glass articles by depositing on the back of the same a coating of copper, or gold, or nickel, or other metals. In the specification, the metal tin is also suggested as a substitute for the above named metals.

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Related

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205 F.2d 185 (Customs and Patent Appeals, 1953)
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Bluebook (online)
77 F.2d 920, 22 C.C.P.A. 1245, 1935 CCPA LEXIS 178, Counsel Stack Legal Research, https://law.counselstack.com/opinion/in-re-langdon-ccpa-1935.