United Advertising Corp. of Texas v. Stimson

89 F.2d 450, 33 U.S.P.Q. (BNA) 274, 1937 U.S. App. LEXIS 3496
CourtCourt of Appeals for the Fifth Circuit
DecidedApril 17, 1937
DocketNo. 8183
StatusPublished
Cited by2 cases

This text of 89 F.2d 450 (United Advertising Corp. of Texas v. Stimson) is published on Counsel Stack Legal Research, covering Court of Appeals for the Fifth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
United Advertising Corp. of Texas v. Stimson, 89 F.2d 450, 33 U.S.P.Q. (BNA) 274, 1937 U.S. App. LEXIS 3496 (5th Cir. 1937).

Opinion

HOLMES, Circuit Judge.

This is an appeal from an interlocutory decree sustaining the validity, as to claims 2, 3, 12, and 13, of letters patent of the United States, Re No. 18,166 reissued August 25, 1931, to Jonathan Stimson for improvements in luminous display or reflector sign's. The appellees, Stimson and American Gas Accumulator Company, were decreed to be the owners of said patent and the exclusive licensees thereunder, respectively. The appellant, United Advertising Corporation of Texas, was adjudged to have infringed said four claims by the manufacture and installation of signs employing reflector units not manufactured or licensed by appellees. A permanent writ of injunction was issued restraining further infringement, and a master was appointed by the court to assess the damages sustained by appellees.

Claim 2 of the patent in suit refers to a light" source and luminous sign made of letters displayed by means of a reflecting area, composed of a series of reflecting units arranged in a contiguous relation, and constructed and positioned to cause a definite spread of the reflected light and to confine it to a selected field. Claim 3 is identical with claim 2, except therein it is specified that each of the reflecting units shall be so constructed as to cause a definite beam-spread of uniform intensity, the composite beam from’ all the units being confined within the selected field. Claim 12 refers to a reflecting sign in which the characters are outlined with units of reflecting areas adapted to reflect incident light from a distant source in the general direction of its origin with a slight spread of the reflected light. Claim 13 is the same as claim 12, except that the sign is described as having reflecting units arranged along the strokes of the characters.

Nowhere in the patent is there a description of the reflecting area or of the reflecting units, nor is there any direction as to how such reflection is to be accomplished. In the drawings accompanying the application, illustrations are given which disclose that the patentee contemplated the use of pressed or molded glass plates made up of cube-cornered prisms. These plates are known to give the effect of a multiplicity of contiguous triple reflector units. The sign which it is alleged infringes the patent is made up of multiple lens-mirror buttons, also known to have a retroreflec-tive effect on the light falling within their range of operation.

An ideal triple reflector would be made up of three triangular plane mirrors so shaped and placed that each would be at right angles to the other, forming a prism having a front or base which would make an equilateral triangle. In addition to the base, this prism would have three triangular sides,, each with a right angle at its apex and 45 degree angles at its base. When a ray of light traveling toward the base of the prism, in a line of not too great deviation from the perpendicular thereto, would strike one of the plane mirrors, its reflection being in accordance with the rule that the angle of reflection is equal to the angle of incidence, it would be reflected to a second mirror, thence to a third, thence back to its source, much the same as if it had encountered a single plane mirror perpendicular to the ray and of a size and shape equal to the projection of the triangular base on a plane perpendicular to the course of the light. This is because each of the three reflectors, being set in a different plane, and all being at angles with any plane passing through the line of direction in which the light travels, would reflect the light at angles which, when projected on any plane passing through the line of light, would total 180 degrees.

However, it is elementary that unre-fracted light does not travel in parallel lines, but that every beam is traveling with a definite spread which is in proportion to the square of the distance from its source. It is also known that a plane reflector does not interrupt this spread, but simply changes its direction, so that if the direction of reflection is opposite to the direction of radiation, the light from a single point will have spread over an area with dimensions twice those of the mirror when it returns to its source. It is also known that visible light does not radiate from a single point but, in every instance, comes -from an infinite number of points or a radiant surface. Hence, if the radiant surface is equal in size and shape to the mirror, the reflected light returns to its source in a beam of equal intensity over an area equal to that of the radiant surface, outside of, and immediately surrounding which, there is an illuminated area of diminishing intensity beginning with that of the inclosed area and disappearing altogether when its outside dimensions are three times as great

[452]*452The lens mirror used by appellants does not embody any of the characteristics of the triple reflector. In principle, it focuses the beam of incident light by lens refraction, so that it is brought together at a point on a concave mirror so curved as to have its tangent at the point of reflection perpendicular to the axis of the cone of refracted light. This causes reflection of a cone of identical dimensions, but in which the rays of light have been reversed in their positions. Passing out through the same lens, they are again arranged in substantially the same relation as when they entered. In practice, with corrections for spherical and chromatic aberrations, and a slight deviation from a true focus, the lens mirror button produces a luminous area of uniform intensity with a light spread much greater than that of the incident light. It makes no difference whether the mirror be ahead of the focus or behind it, or whether the light converges in front of the lens, or scatters on leaving it; so long as the rays are not parallel, or nearly so, the reflected light is spread over a field the size of which is determined by the curvature of the lens and mirror, or their relationship to each other.

In the devices used by both appellant and appellees, manufacturing inaccuracies play an important part. In pressed or molded cube prism plate glass, bulges and ridges occur in the surface of the cube faces, or the same condition may result from irregular contraction while cooling. These irregularities are relied upon by ap-pellees to produce a spread in the light. However, another spread occurs because of unavoidable deviations from right angles on the edges of the cubes. A deviation in one angle results in a beam of reflected light which splits into two parts. Two inaccurate angles produce four beams, and three produce six. If the angles could be made accurately, a larger reflecting unit would produce a proportionately larger illuminating beam and beam-spread; but the angles cannot be made perfect, and the resulting split in the light produces dark spots which are the same size as the inaccurate units. Therefore, appellees use a multiplicity of small units in an effort to produce an area from which the reflected light from one unit overlaps that of another, and on which the dark spot resulting from an inaccurately formed cube corner will be as small as possible. The lens mir-' ror button would be useless if it produced a perfect focus upon a correspondingly perfect mirror with perfect corrections for aberrations. Hence, it is manufactured within certain limits of tolerance to produce the desired spread of light. With the irregular cube faces to produce the spread, cube-cornered glass cannot be manufactured with sufficient accuracy to prevent dark spots in the field.

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89 F.2d 450, 33 U.S.P.Q. (BNA) 274, 1937 U.S. App. LEXIS 3496, Counsel Stack Legal Research, https://law.counselstack.com/opinion/united-advertising-corp-of-texas-v-stimson-ca5-1937.