In re Stark

453 F.2d 1401, 59 C.C.P.A. 787, 172 U.S.P.Q. (BNA) 402, 1972 CCPA LEXIS 398
CourtCourt of Customs and Patent Appeals
DecidedJanuary 27, 1972
DocketNo. 8635
StatusPublished

This text of 453 F.2d 1401 (In re Stark) 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 Stark, 453 F.2d 1401, 59 C.C.P.A. 787, 172 U.S.P.Q. (BNA) 402, 1972 CCPA LEXIS 398 (ccpa 1972).

Opinion

High, Judge.

This appeal is from the decision of the Patent Office Board of Appeals affirming the examiner’s rejection of claims 14-18 of appellant’s [788]*788application serial No. 570,382, filed August 4,1966,1 for a “Television Degaussing System With Saddle-Type Coils Adjacent CRT Cone.” Twelve claims stand allowed. We reverse.

The appealed claims were copied from Patent No. 3,340,443 to Rieth and O’Leary (Rieth), issued September 5, 1967, on an application filed April 30,1964. The rejection was based solely on the ground that the claims are not supported by appellant’s application.

The Invention

The invention relates to apparatus for degaussing (demagnetizing) a color television receiver which employs a shadow mask type of picture tube. In such a tube, the shadow mask with hundreds of thousands of small apertures in it is positioned just behind the tube’s viewing screen. The apertures are aligned with trios of red, green, and blue phosphor dots deposited on the screen. An electron gun structure in the tube directs three separate electron beams toward the screen. Each beam passes through only one aperture in the screen at a time, and the trajectories of the beams are adjusted so that each beam impinges on phosphor dots of only one color. The mask “shadows” dots of the other two colors from the beam for each color.

The mask is made of a metallic material which is magnetizable. External magnetic fields, including stray fields and the earth’s field, may cause undesired magnetization of parts of the tube including the mask. Such magnetization tends to deflect the electron beams from their preadjusted trajectories and causes misregistration with the respective phosphor dots. In particular, moving the receiver from one position to another tends to result in misregistration caused by the earth’s magnetic field.

It is well known that metal which has become magnetized can be degaussed by subjecting it to an alternating magnetic field which has an initial strength greater than the strength of the field within the metal and then gradually reducing the strength of the applied field until there is substantially no magnetic flux left in the metal. An early method of degaussing a color television receiver utilized that principle by moving a wire coil energized with alternating current about the face of the picture tube and gradually moving the coil away from the tube.

The present invention utilizes a pair of coils permanently disposed about the receiver tube for automatic degaussing. The coils are connected to an electrical circuit that is operated each time the [789]*789receiver is turned on to briefly energize them, with a decaying alternating current and thus provide an alternating magnetic field that quickly decreases from a maximum value to zero. A shadow mask type color picture tube with degaussing coils is shown in top plan view in Fig. 1 of the application drawing and a front view of the coils (with tube omitted) is shown in Fig. 2.

[790]*790The two coils are designated generally 14 and 15. They are saddle-shapped with front portions 19, 19' extending about the face of the tube 10, longitudinal portions 16,16' and 17,17' extending rearwardly from the front portions, and rear portions 20 and 20' interconnecting the respective side portions. Connections (not shown) between the coils are such that, at a given instant during their energization, the relationships of the directions of current flow in the various coil portions are as shown by the solid arrows in the above figures.

Claims 14 and 18 are representative (emphasis ours) :

14. In a color television receiver, a color picture tube having a display face with a plurality of different phosphors distributed across the display face, said phosphors in the plurality being effective to luminesce with visible light of particular colors when bombarded by electrons:
Electron means for scanning the display face with electrons to excite the phosphor [sic] into luminescing with the particular colors;
A mask disposed in said tube between the face and said electron means, said mask being positioned to shield the different phosphors in the plurality from electrons representing different colors;
At least á pair of coils positioned adjacent the mask at spaced positions and extending in a (direction transverse to the mash to produce a magnetic flux field in the mask without any dead, spot at any position on the face of the color picture tube, and
Means coupled to the pair of coils for energizing the coils with a signal of decaying intensity to gradually reduce the intensity of the magnetic flux field in said mask and degauss the color picture tube.
18. In a color television receiver,
A color picture tube having a display face;
clusters of phosphors distributed over the display face of said tube, each cluster including a plurality of separate primary phosphors each being provided for a different primary color;
a plurality of electron guns each being provided for a different primary color to scan said display face with an electron beam and direct a beam of electrons onto the phosphors having the particular primary color corresponding to the particular gun;
a mask disposed between the face and said electron gun, said mask having a plurality of apertures each being provided for an individual one of the clusters, the mask being made from a material having magnetic properties;
At least a pair of coils disposed outside of the tube and substantially normal to the mash 'and in magnetically coupled relationship to the mask, said coils being disposed on the opposite sides of the mask to produce in the mash flux fields that extend across the mash, and
means interconnected with the coils to circulate an alternating current of decaying characteristics through the coils and produce a magnetic [sic] flux field through the mask of decaying alternating characteristics to degauss the display face of the color picture tube.

[791]*791For present purposes, claims 15 and 16 are substantially the same as claim 14. Claim It differs from claim 14 in that it lacks the recitation that the magnetic flux field is “without any dead spot” on the display face of the tube.

The Rejection

No references are relied on.

The appealed claims were rejected by the examiner “under 35 U.S.C. 112 as 'based on an inadequate disclosure.” What he Obviously meant was that claims 14-18 are not supported by appellant's disclosure. {The claims were based, of course, on Rieth’s disclosure.)

The board sustained this rejection in a short opinion the essence of which is in the following quotation:

The mask recited in the claims, hut not described in the specification or shown on the drawing, would normally be approximately in the plane of the conductors 19-19*' of the present drawing.

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Bluebook (online)
453 F.2d 1401, 59 C.C.P.A. 787, 172 U.S.P.Q. (BNA) 402, 1972 CCPA LEXIS 398, Counsel Stack Legal Research, https://law.counselstack.com/opinion/in-re-stark-ccpa-1972.