Refractolite Corporation v. Prismo Holding Corporation

• Decision Date: 24 February 1941
• Docket Number: No. 181.,181.
• Citation: 117 F.2d 806
• Parties: REFRACTOLITE CORPORATION et al. v. PRISMO HOLDING CORPORATION et al.
• Court: U.S. Court of Appeals — Second Circuit

117 F.2d 806 (1941)

REFRACTOLITE CORPORATION et al. v.PRISMO HOLDING CORPORATION et al.

No. 181.

Circuit Court of Appeals, Second Circuit.

February 24, 1941.

John F. Ryan, Kenneth H. Guild and S. A. Demma, all of New York City, for defendants-appellants.

Before L. HAND, AUGUSTUS N. HAND, and CLARK, Circuit Judges.

L.HAND, Circuit Judge.

This is an appeal from a judgment in an action brought by the plaintiffs to declare invalid PatentNo. 1,902,440, issued to Edwin R. Gill, Jr., on March 21, 1933.The defendants, who were the owners of the patent, counterclaimed, first, by asking that PatentNo. 2,043,414, issued on June 9, 1936, to Fred H. Korff and owned by the plaintiffs be declared invalid; and, second, that the plaintiffs be enjoined from infringing the Gill patent.The judge held both patents invalid and entered judgment in favor of the plaintiffs upon their complaint, and in favor of the defendants upon the counterclaim, so far as it prayed a declaration that the plaintiffs' patent was invalid, but against them so far as they prayed an injunction upon the Gill patent.Only the defendants appealed and the single question before us is as to the validity of the Gill patent, which the plaintiffs plainly infringe.

The patent is for a road sign designed to reflect the headlights of an approaching motorcar.The patent is for a flat sign upon the surface of which a layer of enamel is spread capable of reflecting the beams of the headlights.In this enamel are embedded, up to about one-half their depth, very small glass spheres — less than one thirty-second of an inch in diameter.(The specifications provided that "cubes or other regularly shaped geometrical devices" like cylinders might be substituted, but in practice spheres alone appear to have been used.)Since a sphere is perfectly symmetrical, a beam of light entering it from any angle will be refracted to the same extent; it will also be refracted through an equal angle upon emerging.It is possible to make the beam return in exact parallel with the entering beam by setting a mirror outside the refracting sphere at the proper distance away — called the focal distance which is a fraction of the diameter of the sphere.If the mirror were concave, hemispherical and set at the focal distance off, the result would be that every beam would pass through it to the mirror, back from the mirror to the sphere through which it would pass and it would finally emerge exactly parallel to its direction when entering.A flat mirror will do this only for beams that fall upon the sphere at right angles to the mirror; all other beams will be returned in a different direction from that of their incidence; which means that the sign will reflect its fullest brilliancy to the car only when the car is dead ahead.

Gill did not make a sign which conformed absolutely to these optical demands; it was impracticable to set hemispherical concave mirrors at the focal distance away from the glass spheres, because the mirrors could only be the cups made in the enamel by pressing the spheres into it while it was plastic.It was inevitable in such a construction that the mirrors should be inside the focal distance and a perfectly parallel return of the beam as impossible.Gill met this difficulty by reducing the size of the...