US2307697A - Electronic tube - Google Patents

Description

1943- o. T. MCILVAINE 2,307,697

ELECTRONIC TUBE Original Filed July 9, 1954 i lwi s- Patented Jan. 5, 1943 2,307,697 4 ELECTRONIC TUBE Oran T. McIlvaine, St. Charles, Ill.

Original application July 9, 1934, Serial No.

734,352. Divided and this application Decemher 5, 1940, SerialNo. 368,711

5 Claims. (01. 250-165 This application is a division of my application on Electronic device, filed .July 9, 1934, Serial No. 734,352 which was a continuation-inpart of my application, Ser. No. 209,281, filed July 29, 1927, forElectronic tubes, which appli-.

ction matured into Patent No. 1,965,849, on July 10, 1934.

This invention relates to electronic devices, such as, electronic tubes for use in connection with the transmission and reception of electromagnetic impulses or radio signals.

Attempts have been made heretofore to, combine a photo-electric tubewith a thermionic tube, with the photo-cathode connected with the grid of the thermionic tube in one envelope, but the action was the same as when two separate envelopes were employed, resulting only in a more complex and expensive structure.

The primary object of this invention is to combine a photo-electric tube with a thermionic tube so that the electronic streams are intermingled in controlling the thermionic emission directly by the fiow of photo-emission from the photocathode, the two currents being reactive in the space between the various elements of the tube,

the electronic streams themselves being employed for controlling the action.

The present invention has for further objects thereof the provision of an electronic tube of simple and inexpensive construction which will operate successfully for an indefinitely long period of time; the provision of a simple and inexpensive type of tube which can be used with either direct or alternating current or other sources of light andheat; the provision of a power tube with a light-sensitive electrode for controlling,

by the fiow of photo-emission therefrom, the elec-' tron emission of the thermionic cathode of the tube by changing the potential of either the anode or grid of the tube; and the provision of 'a H light-sensitive power tube, having associated therewith, a light source which may be modu- Fig. 3 is a vertical sectional view of another or modified form of tube; and

Fig. 4 is a'transverse sectional view thereof.

In the form of the invention shown in Fig. 1,

the tube comprises a sealed glass container in the form of an envelope having a side wall I fused at its lower. end 2 to a tubular stem or press 3v which carries the various elementsof the tube.

The tube maybe highly evacuated or' it may be filled with one of the inert gases such as, neon. A The elements of the tube shown in Fig. 1, include o a hot cathode in the form of a wire filament 4, a light-sensitized grid element 5, .ananode element 8, an anode i and a support 8 for the foregoing elements. l

The anode 1 can also be used to collect the. electrons emitted from the hot cathode 4, it being. controlled in accordance with the variation in light impinging on the sensitized grid element'5 supplied from a 1ight source (not shown) fluctuating in accordance with'incoming signals transmitted by a fluctuating current. Both the anode element 6 and the anode 1 may be'used for the same purposeor either one of them may be operated as a photo-anode and the -0ther-asa thermionic anode by the selection and use of proper electrical connections (not shown) as will I be understood byone familiar withthe' art to which this invention relates.

By properly choosing the circuit constants for V these two circuits, many novel results canbe obtained. In this particular device, the grid itself is photo-sensitized and it-varies the hot cathode emission from the filament t to the anode element 6 or the anode 1. Lead wires H), II, l2and l3, traversing the press 3 of the tube, are connected to the anode element 6,-each of the terminals'of the hot cathode 4, the grid element 5 and the' anode 1 respectively. r

lated or controlled by or in accordance with incoming radio signals or electric impulses.

With these and other objects in view, the invention consists in the novel construction, arrangement and combination of parts, hereinafter illustrated and described in some of its embodiments in the accompanying drawing, and

particularly pointed out in the appended claims.

In the drawing, certain illustrated embodi- The sensitizing of the grid 5 in Fig. 1, controlling the emission'of electrons under the influence I of light acting thereon, renders far more elfective the electron stream from the hot cathode to the anode of the thermionic tube, than ifthe photo-emission were used merely to change the I potential on the grid. Each electron emitted by I the gridunderthe influence of light has a much merely to change the potential on the grid. I

In Fig. 3 there is a modified form of tube in r which a photo-cathode-Mlis locatedon the inner I surface of the outer wall 3| of the tube and-it consists of a material, manyof which are known, which emits electrons when exposed to light. An I r anode 32 made of a'net-work of wires which-a1- better control than if it were used lows the passage of light from a heated filament 33 is arranged to absorb and carry away the electrons emitted by the filament 33. The flow of electrons from the cathode or filament 33 to the anode 32 may be controlled by a grid element 34.

The potential of the grid 34 may be controlled by the electrons emitted from the photo-cathode 30 which in this case is on the inside of the tube, and these electrons are drawn to the grid 34, which in this respect is the anode for the photo-cathode 38. This current flow, by changing the potential on the grid 34, thereby controls the electron stream from the hot cathode 33 to the anode 32.

In this form, the grid 32 forms the anode for the photo-cathode 30, while the grid .34 zconsti tutes the anode for the hot cathode 33. Thus the efiect of a much greater gridlcontrol once, thermionic electron flow than if :the voltage of number of tubes formerly thought necessary to produce the desired degree of amplification of radio or wireless signals without objectionable distortion.

The tubes may be either highly evacuated or they may be filled with one or more inert gases commonly used for such purpose.

While the light sources described in connection with the tubes shown in Figs. 1 and 3, are not specifically illustrated in the drawing, it is intended that any suitable source of radiant energy, ivisible'ior invisible, which fluctuates under the influence ofa fluctuating electrical current, might be used in connection with the various tubes Photo-icathodes can be selectively sensitized to =iespohdto'-'difierent frequencies of light by utiliz- -"ing the selective photo-electric efiect which is a grid 32 were varied from. an outside potential. In this Way the electron streams themselves are poses,.such'as where a certain bias voltage is not required on. the grid34, a black emitter can be used which gives no light and has no substantial effect on :the photo-cathode. A cathode of this type would be a caesiated tungstencathode or some similar cathode as describedin the tubes of application, Serial No. 209,281, previously referred to, now Patent No. 1,9 65,849.

Another: manner of using the tube shown in Fig. 3 Lwouldzbe that of using. the wire network 32 as the'grid and using the coil 34 as the anode, in which. case electrons-are supplied to the anode 34 by-the filament 33 which is preferably heated to incandescence for suchpurpose and also for the purpose. of providing-a light source for the excitation of the photo-cathode 30. With this arrangement, the fixed bias on the grid 32 may be varied through the control of the electron emission of the photo-cathode 36 by changing the brilliancy of. the filament 33. light incident upon the photo-cathode would then operate around this point as an operation point.

Light may be admittedto the surface of the photo-cathode through the photo-cathode itself which consists of alight-sensitized transparent film of metalon the inside wall otthe tube, or

e if an opaque coating is used, light can be admitted through either end of the tube by omitting the coating at these p0ints, 0r as is done in the present-case, light can be admitted, through one Any fluctuating side of the tube by omitting the coating there as is done in the tube shown in Fig. 3. Suitable leads 35, 36, 31 and 38 traverse a press 39 sealed in the tube and they are connected respectively l electrons, as for example,the hot and cold cath' odes shown, the latter of which is controlled by a source of light,-so that the operation of the tub.

can be-varied and controlled by means of a light sourcehavingno electrical connection with the 7 tube elements.- a The use of a light source in this manner is of tremendous advantage in some typesof radio work and by the proposed use of the tubes shown herein, it is possible to greatly reduce the 73 characteristic of the alkali and alkaline earth metals'and also by having the light strike the photo-cathode withan angleoi incidence-oi about 60, in -wliich case, the different .metals show a strong maximum of photo-electric sensibility over a very short part or the-spectrum, which-dire i fers withthe dinerent metals: and wmch maxi-t mum enect may be varied through selectionof the propermetals'so:astooccur. at different predeterminedportion's oi' the spectrum. a i

By Iorming the cathode suliaceirom.such

metals as, caesium;--rubldium, potassium' and sotions OI the vlsmiespecti um'. I :l'his pnase'oi: the

invention-mightbe utilized in color television- =1 Work and the transmission: or" images their natural colors.

One or the more important features of I this invention is that or employing a relatively small"- PAOLO-CUITBHVOIE '-primary emlssion -to control i a a relatively large --tnermloniccurrent directly in proportion to th'e photo-current; thereby giving a 1 nigh amplincation 'oi' anorigmarreebleimpulse, and many mOCUIICaBiOIISOf thegenerai" principles- 1 or tube construction--disclosedherein; may be particular -I'orms of electronic eevices shown and described, and the-particular procedure-set :iorth, are presented -Ior purposes -oiexplanation, and I! H that variousmodifications ofsaid apparatus-and procedure can' be made withoutoeparture from this invention as" described -in' the appended claims;

. I claim:

1. An electronic-tube comprisingan envelop'e having assembled therein an electronic cathode' and an anode spaced'thereirom,'a photo-cathode and a pnoto anode' therefor mounted in spaced--- 4 relation" insaid'envelope; one oi' said photo elementsbeing intermediate the first-"mentioned electronic elements, and one ofsaid-electronic elements being in the electron'path formed-bythe photo elements,

2. An electronic'tubacomprising anenvelope a having'assembled therein an electronic cathode and an anode spaced therefronr, a photo-cathode and a photo-ano'de'therefor mounted in-spaced" relation in said e'nvelope,'one of said photo elements being intermediate the first-mentioned electronic elements, and one of said electronic elements being in the electronic path from the photo-cathode to the photo-anode forming intersecting electron paths,

3. An electronic tube comprising an envelope having assembled therein an electronic cathode and an anode spaced therefrom, a photo-cathode and a photo-anode therefor mounted in spaced relation in said envelope, one of said photo elements being intermediate the first-mentioned electronic elements, and the first-mentioned anode being in the electron path of the photo elements.

4. An electronic tube comprising an envelope having assembled in a chamber therein an electronic cathode and anode spaced therefrom and a control element, a photo-cathode and a photoanode therefor mounted in spaced relation in said chamber of the envelope, one of said photo elements being formed on the control element.

5. An electronic tube comprising an envelope having assembled in a chamber therein an electronic cathode and anode spaced therefrom and a control element, a photo-cathode and a photoanode therefor mounted in spaced relationin said chamber of the envelope, one of said photo elements being formed on the control element intermediate the first-mentioned electronic elements, and one of the first-mentioned electronic elements being in the electron path of the photo 15 elements forming intersecting electron paths.

ORAN T. MCILVAINE.

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