US2508098A - Method and apparatus for improving the response of radio-sensitive salts - Google Patents

Description

May 16, 1950 c. CHILOWSKY 2,508,098

METHOD AND APPARATUS FOR IMPROVING THE RESPONSE OF RADIO-SENSITIVE SALTS Filed June 15, 1945 2 Sheets-Sheet 1 18%!147: 22 I g- 'p INVENTOR.

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MORNE'YS CHILOWSKY METHOD AND APPARATUS FOR IIIPROVING THE May 16, 1950 c.

RESPONSE OF RADIO-SENSITIVE SALTS 2 Sheets-Sheet 2 Filed June 15, 1945 i 5 I I 5 2 I'd 'xllrtrlrllnavnnnun. yarn!!! mmvroa.

M t ATTURIVB'Y-S RING J TR/C 7704 RING 3 limit of saturation in order to eliminate the influence of local intensity variations on the image.

The aforementioned catalytic phenomena can be obtained by using audible or supersonic frequencies. But it is preferred to use particularly high frequencies in order to obtain these efl'ects without trouble. These high frequencies permit, on one hand, utilizing the phenomena of mechanical resonance of thin plates made of glass or of piezoelectric quartz, or even an artificial piezoelectric glass, these materials constituting generally a support for the crystalline layer and entraining this layer in vibrations; on the other hand, these high frequencies are useful in order to eliminate stationary waves and nodes of resonance which can be formed when the wave length is of the order of the linear dimensions of the screen support; and finally, the high frequencies make it possible to concentrate easily on the crystalline layer of salt a great amount of energy of the high frequency mechanical waves. It is preferable, for this reasoni'or instance, in television-to use wave lengths shorter than the linear dimensions of the image. For television. frequencies can reasonably vary, for instance, between several hundreds of thousands per second and several millions per second (assuming the supports to be of glass or quartz).

A combination of high frequency with an intensity near saturation can give particularly favorable results. However, oscillations of lower frequency (ultrasonic or even audible) which can be produced by magneto-striction devices may advantageously be used in some cases, due to the power and simplicity of such devices.

The invention also relates to fluorescent powders and to screens covered with fluorescent materials which are used in television tubes and in cathode ray oscillographs operated by a beam or pencil of cathode rays. In these cases it is desirable that the light emission of the fluorescent materials on the screen, excited by the cathode rays, should disappear sufllciently quickly after the cessation of the action of the rays, in order to give place to other following images.

According to the resent invention these screens with fluorescent materials are submitted to the action of Supersonics, or to the action of mechanical oscillations of very high frequency, in quite similar manner as used for the crystalline layer of sensitive salts. When these fluorcscent screens are used for television the application to them of mechanical high frequency oscillations suppresses on them the phenomena of luminous after-glow, i. e., the delay in disappearance of light after suppression of cathodic bombardment. (Most fluorescent powders possess this characteristic.)

The reduction or suppression of the after-glow permits, in television, increasing the number per second) of images available on the screen. In the cathode ray oscillograph the velocity of reproduction can be increased. The application of supersonics to such screens also frequently permits increasing the sensibility of these screens.

The invention will be better understood with the aid of the accompanying drawings given by way of an example, in which:

Fig. 1 represents a detail vertical section of the bottom of a cathode ray tube for television, provided with a sensitive salt screen on a pa electric plate;

Fig. 2 represents diagrammatically the whole of the tube, parts of which are shown in Fig- 1;

Fig. 3 represents a view similar to Fig. 1, show- 4 ing a modification in which the salt screen is on a glass support having piezoelectric plates at its periphery;

Fig. 4 represents a top plan view, on a reduced scale, of the parts shown in Fig. 3;

Fig. 5 represents a modified form of the arrangement shown in Fig. 3;

Fig. 6 represents a view similar to Fig. 1, in which the piezoelectric material is on the outer surface of the tube;

Fig. 7 represents diagrammatically and in vertical section an application of the invention to the control of light passing through a layer of sensitive salt exposed to alpha and beta rays;

Fig. 8 represents a horizontal section on the line A-A of Fig. '7;

Fig. 9 represents a vertical section of an oscillation condenser, similar to that shown in Figs. 3 and 5, used for the control of light;

Fig. 10 represents a modified form of the arrangement shown in Fig. 9:

Fig. 11 represents a detail modification of the arrangement shown in Fig. 10;

Fig. 12 represents diagrammatically a modification applicable to the arrangements shown in Figs. 10 and 11;

Fig. 13 represents a vertical axial section of a cathode ray tube dapted for use as an oscillograph or for television;

Fig. 14 represents a plan view of a doubleresonance oscillation generator;

Fig. 15 represents a vertical section on the line 3-3 of Fig. 14;

Fig. 16 represents a horizontal section of a tube containing a magneto-striction device (shown in plan view);

Fig. 1'7 represents a detail vertical section on the line (3-0 of Fig. 16:

Fig. 18 represents a detail vertical section of a modified form of magneto-striction device, and

Fig. 19 represents a vertical axial section of a cathode ray tube provided with a fluid-type magneto-striction device.

Referring to the drawings, and particularly Figs. 1 and 2 thereof, the cathode ray tube of a television receiver is shown at I, this tube being intended for use in projection of an image on a large screen through a crystalline layer of a sensitive salt, scanned by a cathode ray. A thin plate of piezoelectric material 2 (such as quartz) having transparent metallic electrodes 3, 4 on its upper and lower surfaces is connected by the wires 5, 6 to a source of high electric frequency (not shown) outside of the tube. The plate 2 is adapted for mechanical oscillation in the direction of its thickness, and bears on its upper surface a layer of radio-sensitive salt 1; the electric frequency supplied to the plate being such as to maintain the plate 2 and layer I in high frequency mechanical oscillation. That is, the electric frequency corresponds to the resonant frequency of the plate as modified by the presence of the layer of salt deposited thereon. The layer 1 is scanned by the cathode beam or pencil 8, the electrode 3 being arranged to serve also as the anode of the layer. The plate 2 is shown as supported and secured to the wall of the tube l by suitable supports 9. A transparent metallic cathode may be applied to the top surface of the salt layer it necessary. The arrows in Fig. 2 indicate the passage of light from a source In for projecting the image formed in the layer 1 onto a larger screen I I.

In Figs. 8 and 4 the layer of sensitive salt I is shown as being deposited on a glass plate l2 S whlchdszrelativelyethick ahsi sinel'ia m Miter:- Ders tma. relatively;thinecentek no l l neli acne which ;the..salt layenis depqsitedt, lfii flo lec l-fmr quartmplates m are-mountedi.at-.selec t drn inmr on all aroundtherperinhery: of thelglasslp ate I21; as. shown inliigt-A theiquarta p ate-str ct! 1 203: vidediwith 5 suitable v electrodes and connections and being arranged to oscillate axially: f: he: plate-l 2.; The; highs-frequencymechanl ali osotllations thus communicated .to. he pla e irade: concentrated in: the thirccenterport o :W iit they can readily reach-sneatintensitm Glam-11 1: fmthe oscillations at the individual quartz-plates i4); andresultotcoursei inicorresponding oscil's lation, of: the. salt layer h The assembdy: or" parts; 1, l2, l3 and I4 is shown-as mountedin-the-cathr. ode; ray; tube i by meensioisupportsiii. at, any suitable character;

Fig. ,5, shows the same assemblv. 1? arts.

ed one cathode-ray tubeJn-such amannen' h ik theglass plate." constitutes thevend-of thetubw thesidewalls 16 of; the tube being cemented on welded to; the upper surface ofthe-plate. 1 163.15 its peri hery. This arranizementhaethe adYfiJ r" tage thatlthe quartz; plates Ii are. located ou side the tube. Theum-ultiple; oseillationl-generalrs- (plates It) may be.replaced by a-singlecircular genemton for. instance,.- of.- artiflcial-or synthe ic: piezoelectric; materialirinwhich case the. periphcry of the-plateltwoulda be circular, It is; also possibleitc use oscillation-generators oithe DieZOeelectric sandwich type, or (for lower; frequencies suitably adjusted. generators, operati a :by, masnetoestrictlon.

A simplifled arrangement is: shown-m fia. 6 where the, layerotsensitive. salt, crystals; i is de-. posited directly on the wall of the cathode ray tube l.. with the .inte 'pos mmnlyroi the transparen anode Mechan cal sc llatio s. are

c mmunicated ltorthe layer 1 a from tMhottcm-mli f: the tube on whichzls' a. ie o lectric quartz plate I8 having electrodes-.18 and g:- Ii-ha plate Ir .may be: annularas shown;- lealging an pen g-. opposite e'layer i. r-.,it; ea-be1 solid-ma in-.-w:hichcase theec rodes mus e transparent. a least: -in; -theres o po te he said layer. The wall:of theituberadjacentthe plate I85 should-be oi niiormw bicknesa o. form. withe -the. p1ate,-. abody: canshle otw h a ina at. a. definite resonant. frequency; of: m hanica oscillations;

Fi s.- 7 and firshows heannhcs ionoi the in: vention to the control of llght mssingthliollgh, a m d iens ti e salt cr s a s; lph and betairays; and blacken thereby, s ch-cone rol beinaeiiect dxbyivariation or. hes etrie el tential applied-to the lay r, Ill-Fla; a ht m i t e sourced! is concen ra ed-hr he-.iens-u-Qn the bed of crystals 2| carried by a 3 131, support 15.: eiradi a t vesubs an ersuchas rad um-m y ezm orr atcd-iin th bed r crystals 2,. or enl ced outside-midwa T e e szt edsfl lie-21% app y to he flan fle d otv e ect ic mt ntiel which may. qwarlefitaadrw ichr hl imbleits ulation or'by the modulation oiintensity-.oi-the applied rays, determines and modulates the dew arse r opacityoptical c n ssl ot he ed-o crystals. The support 25 constitutes the. project-i ing endoi a conical or prismatic gless-body-- 20, The generator ofhigh frequency mechanical os-l cillations, shownas aiq lartz plate having electrodes 39,- 3l;,' is fixed on the large end of: the body 28 and the oscillations generated therebyarp c ncentrated to a high intensity as they are transmitt d tothe. concert 35,.

6. 11 mm!) -.-.frpsma snmeqh alea wilieti ne bussnn ea to" t e. bed! 1 a mor r idresronae 0a. variat on; Qt asein) i ed-1 and p mithisber .trcquen ie l t la o of be ishtrassad or ton sd' he f ry ciila ienstronr ile-res n io g e A modified liahtecontrol-deviceis shown in Fig. ld-wherein a bedoicrystals JSJsplaced between smaller ends-pl. oscilll ation-condensmg cones or-prisrns 16,-}?- (eaqlr sirnilar to-thevbody 28,-F ss. 7 and 8), thelarger endsot which bear. oscillanon-generators ( quartzplatesl 38,38 having suitable electrodes electrodes 40, 4|; betweenv the'bed-J} and the ends'of-the condensers 36,131 applythe modulated ifleld to said bed and need not, caagpe transparent, The light passes through the bed 35 in a direction perpendicular to the? dire tion-este med, as indicated by the arrows. Themed; ot-salt-crysta1amay, if desired, besubdivideddnto separate layers, as indicated in my 9. 3: WQIQ 3 ho n Separated a dfi almldelwtwdw 4 a a e: in-sign with ,thaelectrodesjll and t.

According to bedpt crystals' 43 may beemm edbetwaeaiha nd 1 barsM,a1-rangedv tooscillate in-resonanceaocording-to their length.

These bars-may be ot-iquarts-and maintained inoscillation by:.tranrn ersev orlongitudinal electric fields froma suitable; oscillating circuit, not shown; or theyb 9! nickeland maintained in resonant oscillation bymagneto-striction in a known nn r.-

Fig is shows apathoderay tube 45 having a 1ayer--oI --fluorcscent material, 4% constituting a screenpn-theinneasiaiace oi; its-end wall; such r ube s- 4Q: as oscillosmphat ie isi ar emduct omopiat piezw electric nus-MAI, {h ving} tran p e electrodes. 48, 49 is applied to the outer surface of the endwall of thatllbealwith the best possible mechanical-continuitylwand the screenllfinmay then be.

' ai tsln ddn me bani lil iony he connection Ofj-thfleleqtrqdes 48, inan oscillating. circuit-halting aJrqquenoy- .correspqnding t0 the resonancaiotith platepll end wallof the tube, and-scree lgthe lend-o1 the (tube is curved assho nw h nm.-Plate m sn with the ame cus omer, .17 1 3 ma e t may made otmflfleielriwne edfle c ass. in w i h a i e-cl ned; would-b insidetube- Fiss 1i Ddrf1 shall-- a. ar a a supporting a layer of radio-sensitive salt 5i and having piezoelectric quartz plates 51 d} arranged in cults iour-sidenedges; suitable e mdes. r id d 9.:- that h a z platesrwilloscillatdmechanicalw in the a direction ot.-their thickness. The cl ssmate is so proportioned that it can havcmultiple resonance in thedhection. oi itslength and width and; will resonate in-thedireetion 01' its, thickness when oscillations at. a suitable. frequency, with overtones are applied tothe edgeshy the quartz plates 52 The device. shown in Figs. 14 and 5 steri se nssathode ra tube or t i e medicated. tmz imtance. i 1 a id-.

Fismfi and-1' shew; admin 18 Plat s A 7 supporting a layer of radio-sensitive salt 55 and having fitted to its periphery a magneto-striction ring 56 (for instance, of the Kallmeyer type as shown in German Patent No. 620,872 of 1934). The parts just described may be mounted within a cathode ray tube 51, of the types shown in Fig. 2 or Fig. 13; or the plate 54 may be arranged to constitute the end wall of such a tube, as shown in Fig. 18, the side walls of the tube being sealed to the upper surface of the plate at 58, 58 so that the ring 58 is outside of the tube. When the ring is connected in a suitable electric circuit to act as an oscillation generator its oscillations are communicated to the glass plate as waves converging toward the center, and the layer of salt on the surface of the plate is thereby strongly oscillated.

The cathode ray tube 59 shown in Fig. 19 has its bottom formed by a double-walled hollow body 60 containing a fluid 8! (preferably non-conducting). The periphery of the body 60 is enlarged somewhat to accommodate a magneto-striction ring 62 (similar to the ring 58 in Figs. 17 and 18') which is immersed in the fluid BI and transmits oscillations to said fluid and thus to the layer of radio-sensitive salt 63 on the upper surface of the body 60.

Since the improved response of the salts described herein results from the multiplication of defects" or fissures in their crystalline structure by rapid oscillation of the salts, it is also contemplated that the salt crystals may be subjected to the prolonged action of high frequency mechanical oscillations prior to their use or during the formation of the crystalline layer. Such pre-treated salts exhibit a more rapid and, particularly, more intense response to the several radiations to which they may be sensitive.

Description of parts of the devices shown as "glass" is not intended to be restrictive, but includes materials which may be functionally equivalent, such as certain plastics. The mounting of oscillation generators in or on cathode ray' tubes should, of course, be eflected with due regard for the possible interference of the oscillations with the cathode ray apparatus; thus the connections between the generator and the tube may need to be of a suitable vibration-insulating type.

It will be understood that the drawings herein are largely diagrammatic as to their dimensions since, for instance, the layer of salt and the quartz plate are generally or frequently of such thinness that it would be dimcult to show them with strict accuracy in small-scale drawings. It

will also be understood that various changes may be made in the form, construction and arrangement of the several parts, without departing from the spirit and scope of my invention, and hence I do not intend to be limited to the details herein shown and described, except as they may be included in the claims.

What I claim is:

1. The method of improving the response of radio-sensitive salts which includes, providing a compact solid body of radio-sensitive halogen salt, applying an electric field to said salt, exposing said salt to radiations adapted to modify the opacity of said salt, projecting a beam of light on a line passing through said salt, and subjecting said salt to the action of mechanical oscillations of at least audio-frequency simultaneously with the action of said electric field and said radiations.

2. The method of improving the response of radio-sensitive salts which includes, providing a compact solid body of radio-sensitive halogen salt,

app ym an electric field to said salt, exposing said salt to radiations adapted to modify the opacity of said salt, projecting a beam of light on a line passing through said salt. and subject- 1 18 said salt to the action of mechanical oscillations of greater than audio-frequency simultaneously with the action of said electric field and said radiations.

3. The method according to claim 1 in which the salt is in the form of a thin layer and in which the electric field is applied in a direction normal to the surfaces of said layer.

4. The method according to claim 2 in which the salt is in the form of a thin layer and in which the electric field is applied in a direction normal to the surfaces of said layer.

5. Means for improving the response of radiosensitive salts comprising, a compact solid body of radio-sensitive salt having the characteristic of exhibiting variable opacity when submitted to electronic bombardment, means for applying rays adapted to form opacity images in said salt, and a generator of mechanical oscillations in mechanical connection with said salt.

6. Means according to claim 5 in which the generator includes a piezoelectric plate.

7. Means according to claim 5 in which the generator includes a magneto-striction device.

8. Means according to claim 5 in which the salt is carried substantially directly by a piezoelectric plate, and in which the generator includes said plate.

9. Means according to claim 5 in which the salt is carried substantially directly by a glass element, and in which the generator includes a piezoelectric plate in mechanical connection with said element.

10. Means according to claim 5 in which the salt is carried substantially directly by a' glass element, and in which the generator includes a magneto-striction device in mechanical connection with said element.

11. Means for improving the response of radiosensitive salts comprising, a compact solid body of radio-sensitive salt, a solid support therefor, and a generator of mechanical oscillations in mechanical connection with said support, the mass of the supp rt adjacent its connection with the generator being substantially greater than the mass adjacent the salt, whereby the oscillations communicated to the support by the generator are concentrated to a higher intensity in the area of the body of salt.

12. Means according to claim 11 in which the support is relatively thick at its periphery and relatively thin at its center, and in which the generator is connected to the periphery of the support and the salt is supported adjacent the center thereof.

18. Means according to claim 11 in which the support is relatively thick at one end .and relatively thin atthe other end, and in which the generator is connected to the thick end and the salt is supported adjacent the thin end.

14. Means for improving the response of radiosensitive salts comprising, a thin layer of radiosensitive salt, means for directing a beam of cathode rays on said layer, a piezoelectric quartz plate adapted for mechanical oscillation in the direction of its thickness, and transparent electrodes on the opposite surfaces of said plate, the layer of salt being supported on one of said surfaces.

15. Means for improving the response of radiosensitive salts comprising, a thin layer of radiosensitive salt, means for directing a beam of cathode rays on said layer, a substantially circular glass support for said layer, the layer being disposed in the center of the support, a plurality oi piezoelectric quartz plates secured to the periphery of the support, and electrodes on opposite faces of said plates.

16. Means according to claim 15 in which the quartz plates are adapted for mechanical oscillation in the direction of the plane of the support.

17. Means according to claim 15 in which the support is relatively thick at its periphery and tapers toward a relatively thin area at its center.

18. Means according to claim 15 in which the support forms one end of a cathode ray tube.

19. Means for improving the response of radiosensitive salts comprising, a thin layer of radiosensitive salt, means for directing a beam of cathode rays on said layer, a glass support for said layer, an annular piezoelectric plate secured to the surface of the support opposite to the surface which supports the layer, the center opening in said annular plate being disposed opposite the layer of salt, and annular electrodes on opposite races of said plate.

20. Means for improving the response of radiosensitive salts comprising, a thin layer 01' radiosensitive salt, means for directing a beam of cathode rays on said layer, an oscillation-conductive support for said layer, and a magneto-striction REFERENCES CITED The following references are of record in the file 01' this patent:

UNITED STATES PATENTS Number Name Date 2,184,125 Sokolofl June 27, 1939 2,185,379 Myers et al. Jan. 2, 1940 2,231,960 Smith Feb, 18, 1941 2,233,037 Smith Feb. 25, 1941 2,292,655 Wesch Aug. 11 1942 2,330,171 Rosenthal Sept. 21, 1943 2,337,569 Pietschack Dec. 28, 1943 FOREIGN PATENTS Number Country Date 494,743 Great Britain Jan. 22, 1937

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