McCreary v. Zworykin

55 F.2d 445, 19 C.C.P.A. 990, 1932 CCPA LEXIS 69
CourtCourt of Customs and Patent Appeals
DecidedFebruary 8, 1932
DocketNo. 2848
StatusPublished
Cited by2 cases

This text of 55 F.2d 445 (McCreary v. Zworykin) 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
McCreary v. Zworykin, 55 F.2d 445, 19 C.C.P.A. 990, 1932 CCPA LEXIS 69 (ccpa 1932).

Opinion

Lenkoot, Judge,

delivered the opinion of the court:

This is an appeal in an interference proceeding from the decision of the Board of Appeals of the United States Patent Office, affirming the decision of the examiner of interferences, awarding priority of invention to appellee. The invention involved is an improved method and apparatus for television. The issue is embraced in -five counts, of which counts 2 and 3 are illustrative and read as follows:

2. In a viewing device for television systems, a screen, means for producing an image on one face of the screen, means for causing a cathode ray to explore the other face of the screen, and means between the faces for establishing conduction transverse to the screen at each point while the cathode ray acts at said point and preventing conduction at other times.
3. Apparatus of the character described comprising a resistance element, whose resistance varies with its illumination, means for forming an image on the element, and means comprising a movable cathode ray for including in an electric circuit successive small areas of said element.

Some of said five counts had been issues in other interferences between appellant, appellee, and other applicants, but said interferences were later consolidated with this interference.

Appellant’s application was filed on- April 10, 192é, and that of appellee was filed on December 29, 1923. Appellee therefore is the senior party.

The principal questions before us relate to the transmitter cathode-ray tube disclosed by Zworykin, the principal features of which may be summarized as follows:

In one end of the tube is a hot cathode and a tubular anode, between which there is placed a diaphragm, said diaphragm having a small hole therethrough for the purpose of forming the cathode ray into a thin beam. About midway of the tube there are two plates which are connected to a relatively high frequency generator, the effect of said plates being to create an electrostatic field, which field varies with the frequency supplied. At this point there are also [992]*992two coils, connected to a generator of relatively low frequency, said coils being so positioned as to produce a varying electromagnetic field which is parallel to the electrostatic field produced by the plates above mentioned. Further along in the tube there is mounted a plate, referred to- in the decisions of the Patent Office as the “ composite ” plate, which is mounted in such manner that the portion of the tube lying beyond said plate is sealed from that part of the tube containing the anode, diaphragm, cathode, and plates heretofore adverted to. This conrposite plate is made up of a thin sheet of aluminum foil, which is presented toward the cathode; on that side of said aluminum foil which is removed from the cathode there is a layer of aluminum oxide; on this, in turn, there is a film of photoelectric material, such as potassium hydroxide. The tube is filled with a low-pressure gas, such as argon. The aluminum oxide of the composite plate is normally an insulating layer preventing conduction between the photo-electric material and the aluminum foil. The last element within the tube proper is a grid, said grid being interposed between the composite plate just discussed and a lens, which lens is mounted on the outside of this end of the tube. The lens is to enable the light projected from the image to be broadcast to be focused upon the photo-electric layer of the composite plate.

The operation of the tube, as disclosed in Zworykin’s application, is as follows: The light from the image being transmitted is focused, by means of the lens, upon the photoelectric side of the composite plate. The photoelectric material gives off electronic emissions which are proportional to the degree of illumination reflected by the image ; this electronic emission serves to bridge the gap between the photoelectric element of the composite plate and the grid interposed between said plate and the lens. The electrostatic and electromagnetic fields set up by the plates and coils respectively so cooperate that the cathode ray is brought to traverse, “ point by point,” the entire area of the aluminum foil side of the composite plate, completing spch traverse, it is stated in Zworykin’s specification, in 1/32 of a second. When the cathode ray bears upon any point of said aluminum foil area, it penetrates it and the effect is that through this point there is established conduction between said aluminum foil and the grid. These elements, the aluminum foil and the grid, are connected to a source of supply, and current flows from one to the other when such conduction has been established by the cathode ray. Such current is, in turn, modulated by the varying degrees of electronic emission at different points of the photoelectric material. Thus there is set up an electrical current which is modulated in accordance with the varying degrees of light intensity on the different points of the photoelectric material; such modulated current is reflected through a series of amplifying devices not necessary here [993]*993to be considered, and finally the impulses broadcast from the antenna of the transmitting station reflect the modulations of the current flowing through the aluminum foil to grid circuit of the cathode ray transmitting tube.

Prior to the consolidations of interferences above noted, as to counts 1, 2, and 3, which were in separate interferences, appellant moved to dissolve upon the ground, among others, that the television system and transmitter described in appellee’s application was inoperative ; also upon the ground that counts 1 and 3 were misdescrip-tive of appellee’s disclosure. Each of these motions was denied by the law examiner. In his decision denying the motion to dissolve as to count 3 (interference No. 55448), there is found the following:

* * * It is not evident that any aluminum foil of the thickness originally given by Zworykin could satisfy these conditions but the device including Plate 32 can not he held so inoperative as to require dissolution of the interference if it can be made operative by electrical skill without invention, and Zworykin should be allowed an opportunity to establish the operativeness of his device by testimony if necessary. * * *

In the law examiner’s decision denying the motion to dissolve as to count 2 there is found the following:

The motion to dissolve by McCreary is practically a repetition of a motion to dissolve as to Zworykin in interference No. 55448, Farnsworth v. Reynolds v. Case v. Sabbah v. McCreary v. Zworykin. For reasons stated in the decision of the law examiner in that interference the motion by McCreary is denied.

In his decision denying the motion to dissolve as to count 1, the law examiner said:

The motion by McCreary is directed to practically the same points of insufficiency and inoperativeness of Zworykin’s disclosure that are advanced in interference No. 55448 and a repetition of the discussion is not deemed necessary.

The record does not show any motion to dissolve the interference as to counts 4 and 5.

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Bluebook (online)
55 F.2d 445, 19 C.C.P.A. 990, 1932 CCPA LEXIS 69, Counsel Stack Legal Research, https://law.counselstack.com/opinion/mccreary-v-zworykin-ccpa-1932.