US2454204A - Cathode-ray tube - Google Patents

Description

NOV. 16, 1 948. c RAYMOND 2,454,204

CATHODE-RAY TUBE Filed Dec. 17, 1945 I INVENTOR. I RICHARD 0. RAYMOND A T TO R/VE Y Patented Nov. 16, 1948 CATHODE-RAY '1 UBE Richard C. Raymond, State College, Pa., assignor to the United States of America as represented by the Secretary of War Application December 17, 1945, Serial No. 635,587

1 Claim. 1 The invention relates in general to cathode ray oscilloscopes and in particular to a cathode ray tube having a vacuum tube amplifier incorporated within its envelope.

as an anode, will be controlled by the bias on the control grid 5.

The above describes a simple embodiment of the invention in which one of the deflecting In the conventional type of oscilloscope, in 5 plates is used as an anode for the vacuum tube which a separate amplifier is used, the maximum amplifier. It is, of course, obvious that the vacfrequency which can be presented on the screen uum tube amplifier may have a separate anode of the cathode ray tube has a definite upper directly connected to the deflecting plate of the limit. In most instances, the highest frequency cathode ray tube by a short direct length of wire. which may be presented is limited, among other This would, of course, be a more practical form things, by the capacitance associated with the since a tube utilizing merely the deflecting plate plate of the final amplifier tube, the capacitance of the cathode ray tube would not be a ver associated with the deflecting plate of the cathefiicient amplifying device. ode ray tube and the capacitance of the leads In the operation of the device, a signal applied connecting the tWo plates. to the control grid 5 will vary the anode current It is an object of this invention to device a flowing through resistor 4 and will accordingly cathode ray tube which may be used for the vary the potential difference between deflecting presentation of very high frequencies. plates 2 and 3. The amount of deflection of It is a further object of this invention to re the electron beam in the cathode ray tube deduce the distributed capacitance in the circuit pends on the difference in potential between the between the anode of the vacuum tube amplitwo deflecting plates. It can be readily seen, fier and the deflecting plate of the cathode ray therefore, that the amount of deflection of the tube. electron beam can be controlled by the applica- Other objects and advantages will become tion of a signal to the control grid 5. readily apparent by referring to the hereinafter The highest frequency to which the device of described specification. this invention can respond is greatly increased The tube consists of a conventional cathode over conventional arrangements since the disray tube with a vacuum tube amplifier which has tributed capacity of the connection between the one or more grids and in which the vacuum tube 9 vacuum tube amplifier and the deflecting plate anode is also one of the deflecting plates of the can be greatly reduced. cathode ray tube or in which the anode of the The vacuum tube amplifier is shown in the figvacuum tube amplifier is electrically connected ure as a triode in which one of the deflecting to one of the deflecting plates. plates serves as its anode. The figure was drawn The cathode ray tube of this invention is capain this manner solely for the sake of simplicity ble of responding to much higher frequencies and for the purpose of illustration. It is not inthan conventional cathode ray tubes since the tended that the invention be limited to the use distributed capacitance, which in most cases of a triode since any well known type of tube can limits the upper frequency to which an oscillobe placed within the envelope of the cathode scope can respond, has been greatly lowered by ray tube and have its anode connected to one including the vacuum tube amplifier within the Q of the deflecting plates. envelope of the cathode ray tube. It will be apparent that there may be devia- The invention will be best understood by ref-- tions from the invention as described which still erence to the single figure of the accompanying fall fairly within the spirit and scope of the invendrawing which shows a simple embodiment of the tion. For example, if desired, two vacuum tube invention. amplifiers may be located within the envelope of The figure shows a cathode ray tube I which the cathode ray tube in order to provide push-pull has conventional deflecting plates 2 and 3 with amplification for the deflection signal. leads connecting the two deflecting plates to, a Accordingly I claim all such deviations which source of potential. A resistor 4 is included befall fairly within the spirit and scope of the twee d flec i plate 3 a t e source o poinvention as identified in the hereinafter claim. tential. A control grid 5 is disposed adjacent What is claimed is: to the deflecting plate 3 and the cathode B is In a cathode ray oscilloscope, a source of posialso included within the envelope in such a mantive potential, a cathode ray tube including an her that the stream of electrons from the cathvacuated envelope and a beam forming cathode,

ode 6 to the deflecting plate 3, which serves also a pair of deflecting plates, means for electrically ner that ithe 'flow of 1 current through SaldeI'BSiStOr' means may be controlled-Joy the:potentiallapplied.

to said control grid, the voltage drop developed across said resistor by said current being im=-- pressed directly upon said one deflection plate.

RICHARD C. RAYMOND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Wienecke June 20, 1939 Maggio Feb. 24, 1948

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