In Re Washburn

182 F.2d 202, 37 C.C.P.A. 1094, 86 U.S.P.Q. (BNA) 108, 1950 CCPA LEXIS 258
CourtCourt of Customs and Patent Appeals
DecidedMay 9, 1950
DocketPatent Appeal 5684
StatusPublished
Cited by7 cases

This text of 182 F.2d 202 (In Re Washburn) 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 Washburn, 182 F.2d 202, 37 C.C.P.A. 1094, 86 U.S.P.Q. (BNA) 108, 1950 CCPA LEXIS 258 (ccpa 1950).

Opinion

JOHNSON, Judge.

This is an appeal from the decision of the Board of Appeals of the United States Patent Office sustaining that of the Primary Examiner rejecting method claims 7 and 8 of an application for á patent for the analysis of mixtures with a mass spectrometer. Four apparatus claims were allowed.

The claims in issue read as follows:

“7. In a process for analyzing a gaseous mixture by mass spectrometry involving the production of ions from gas molecules and the projection of the ions through an aperture by impressing an electrical potential on the ions, the improvement which comprises subjecting the ions to an electrical potential having a component parallel to the axis of the aperture and a component transverse to the axis of the aperture.
“8. In a process for analyzing a gaseous mixture by mass spectrometry involving the production of ions from gas molecules in an ionization region and the projection of the ions from the region through an aperture by impressing an electrical potential on the ions, the improvement which comprises subjecting the ions, prior to their passage through the aperture, to a voltage which has a component in a direction transverse to the axis of the aperture.”

Claim 3 is representative of the allowed apparatus claims and reads as follows: “3. In a mass spectrometer having an ionization chamber provided with a first electrode having an ion outlet aperture, and means for impressing a potential across at least a portion of the chamber to the aperture for propelling ions from the chamber through the aperture, the combination which comprises a plurality of electrodes mounted in the chamber, opposite the aperture, means for impressing different potentials between the respective electrodes of the plurality and the first electrode, means for introducing molecules into the space between the first electrode and the plurality of electrodes, and means for directing an electron beam into said space.”

All of the allowed claims define an apparatus which includes an ionization chamber with a first electrode having an ion outlet aperture, a plurality of electrodes mounted in the chamber opposite the aperture, and means for impressing different potentials between the respective electrodes of the plurality and the first electrode.

In mass spectrometry, gas molecules are converted into ions by bombarding the molecules with a beam of electrons in an ionization chamber. As they are formed, the ions are projected through an aperture by an electrical potential established between the apertured electrode and a “pusher” electrode disposed elsewhere in the chamber. After passing through the aperture, the accelerated beam of ions passes through a transverse magnetic field which deflects the ions into curved and diverging beams of ions of different specific mass, forming thereby a spectrum of ions of different weights. By varying the accelerating potential or the magnetic field, the radii of curvature of the ion beams may be changed, permitting each beam to be focused successively on an outlet slit through which they pass onto a collector electrode. There the ions give up their electrical charges, the amount of charge in each case being the measure of the abundance of each kind of ion.

Appellant’s improvement is concerned with that phase of mass spectrometry involving the establishment of the electrical potential to propel the ions out of the ionization chamber. Specifically, his improvement resides in subjecting the ions to an electrical potential which includes a component transverse to the axis of travel of the ion beam through the outlet slit. Appellant provides a potential which includes a component transverse as well as parallel to the axis of ion travel. This is said to enable a sharper focusing of the ion beams on the collector plate, improving the sensitivity of the operation, and resulting in more accurate analysis.

*204 Appellant’s specification contains a description of an apparatus for accomplishing his improvement. The structure consists of an ionization chamber into one end of which gas molecules enter through a, conduit disposed between two “pusher” electrodes. At the other end of the ionization chamber portion of the structure are two parallel plates or electrodes transversely disposed and provided with a central opening, termed outlet slits. Beginning just past the end of the ionization chamber, the structure consists of a semicircularly curved tube, at the opposite end of which is a slit opening upon the electrode collector plate. An electron beam passes through the ionization chamber, ionizing the gas molecules. The ions are propelled through the outlet slits by means of an electrical potential impressed between the first plate or electrode and the “pusher” electrodes. The ions are further accelerated by an additional potential impressed upon the first plate and the second parallel transversely disposed plate. Before appellant’s improvement, but one “pusher” electrode was used. In his apparatus, one potential difference is impressed between one “pusher” electrode and the first of the beforementioned plates, and a different potential difference is impressed between the other “pusher” electrode and the first electrode plate. The effect of using the two “pusher” electrodes with the different potentials is to subject the dons to a voltage having a component transverse to the axis of the slits as well as a component parellel to that axis. Appellant characterizes this effect as a “crossed field.”

The allowed apparatus claims embrace the apparatus set forth in appellant’s specification.

The involved method claims were rejected by the examiner on the ground that they recite merely the inherent functions of appellant’s apparatus. The examiner stated that the improvement recited in the method claims consists of the step of subjecting the ions to an electrical potential having a component transverse to the axis of the first electrode, and held that the step is automatically performed when the apparatus is functioning normally: The board agreed that the step of subjecting the ions to a voltage having a transverse component is “the inherent function or result of the means for impressing different potentials between the pusher electrodes recited in the apparatus claims.”

Appellant contends that the method defined in the appealed claims employing the “crossed field” is independent of the apparatus employed for producing it, and consequently that the appealed claims should be allowed. After the board’s decision was rendered, the appellant filed a petition requesting reconsideration. In his brief in support of the petition he alleged that prior to filing the involved application he had developed at least two types of apparatus for carrying out the method defined by the appealed claims. In support of his petition, appellant filed an affidavit of Sibyl M. Rock, a mathematician employed by the Consolidated Engineering Corporation as a Technical Consultant and assigned to research and development of mass spectrometers. Affiant stated that in October 1941 he prepared a report on experimental work then in progress in mass spectrometry, and called attention to three pages of his report, appended to his affidavit, “which show that at least as early as October 8, 1941, Dr. Washburn, the Applicant * *, had conceived of at least two means for producing a transverse potential component in an ionization chamber to increase the sharpness of focus and the sensivity of mass spectrometers.” Mr.

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Bluebook (online)
182 F.2d 202, 37 C.C.P.A. 1094, 86 U.S.P.Q. (BNA) 108, 1950 CCPA LEXIS 258, Counsel Stack Legal Research, https://law.counselstack.com/opinion/in-re-washburn-ccpa-1950.