US2657133A

US2657133A - Electron tube marking

Info

Publication number: US2657133A
Application number: US48551A
Authority: US
Inventors: Weingarten Joseph
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-09-10
Filing date: 1948-09-10
Publication date: 1953-10-27
Anticipated expiration: 1970-10-27

Description

1953 J. WEINGARTEN ELECTRON TUBE MARKING 2 Sheets-Sheet 1 Filed Sept. 10. 1948 FIG.|

22 l3 8 I 7 I 1\ l! x h I DEFLECTION 43/ PQWER SIGNAL SUPPLY SOURCE FIG. 4

' INVENTOR JOSEPH WEINGARTEN ATTORNEY Oct. 27, 1953 Filed Sept. 10, 1948 2 Sheets-Sheet 2 INVENTOR JOSEPH WEINGARTEN ATTORNEY Patented Oct. 27, 1953 UNITED STATES PATENT OFFICE 18 Claims. (Cl. 95-5) (Granted under Title 35, U. S. Code (1952),

sec. 266) This invention relates in general to the electron tube art and, more particularly, concerns the utilization of photographic apparatus and techniques for individually processing characteristic markings upon cathode ray and similar electron tubes. The present application is a continuation-in-part of the application of Joseph Weingarten, Serial No. 669,557, filed May 14, 1946, for Cathode Ray Tube Calibration, which matured into Patent 2,449,093 on September 14, 1948.

Cathode ray tubes and similar electron tubes are widely used in electrical apparatus for the observation, recording and measurement of electrical signals. Cathode ray tube applications ex tend into substantially all phases of the electronic art, as in radar, television, facsimile, and the like.

Briefly, the conventional cathode ray tube comprises an electrode structure, known as an electron gun, for generating an electron beam within a glass or other suitable envelope. The electron beam is normally focussed to a sharply defined point upon a fluorescent screen in the face of the tube, thereby providing a luminous spot. Deflection means in the form of orthogonal electrodes (electrostatic) or coils (electromagnetic) permit displacement of the spot in a predetermined pattern for forming a visible trace upon the screen.

In numerous well-known devices, cathode ray tubes are used solely for qualitative analysis, for

aid in determining maxima and minima, or for image reproduction, and consequently do not require calibration, reference lines, or other substantially fixed visible markings. On the other hand, cathode ray tubes are in extensive use in analytical apparatus, as in oscillographs, spectrum analyzers, radar systems and television test equipment; wherein precise measurements of the trace appearing upon the screen are essential. Markings related to predetermined movement of electrons must be provided for the latter applications.

of the cathode ray tube screen. In radar appli-' cation, a transparent map is often placed before a cathode ray tube plan position indicator so that the relationship of target echoes to the surround ing terrain may be observed visually. lhe application of a transparent map is of particular importance where moving target radar indication is employed, since only echoes of objects in motion appear while radar echoes of the stationary terrain are entirely suppressed.

It is generally known that the deflection sensitivity of a cathode ray tube, defined as the displacement of the fluorescent spot obtained for a unit change of deflection potential or current, is a marked function of the position of the spot upon the screen. Therefore, the aforementioned coordinate scale systems are seriously handicapped by the fact that the distance between adjacent coordinate lines at one point on the tube screen is not representative of a deflection signal magnitude which will cause equal displacement at another point on the screen surface. Calibration of a printed scale must thus be accomplished experimentally, and involves the accumulation of considerable data, which data must be available before cathode ray tube images may be successfully interpreted. Prior cathode ray tube coordinate scales, printed maps, or test patterns have the further disadvantage of failing to take into account faults in tube construction, such as non-orthogonality of the deflection means. Also, these scales do not account for inherent structural variations from tube to tube, and permit errors due to parallax, since such printed indicators are fiat while tube screens are generally warped surfaces. For these reasons, laboratory personnel consistently avoid the use of large deflections and perform measurements in the central region of the tube face whenever possible.

The aforementioned patent fully discloses a cathode ray tube screen marking which successfully permits utilization of substantially the entire visible surface of the tube screen for precise measurement. As described therein, a scale marking individual to the cathode ray tube was photographically obtained by first applying a light sensitive substance, in the form of a coating, over the face of the tube in proximate relation with the fluorescent screen. Operating potentials were then applied, producing a sharply defined spot which was deflected and varied in intensity to trace out a predetermined coordinate system, exposing the light sensitive coating through the glass separation between coating and fluorescent screen. Thereafter, conventional photographic processing of the exposed coating provided substantially permanent coordinate scale markings.

In marking cathode ray tubes in accordance with the procedures outlined in the aforementioned patent, certain problems may be encountered, particularly where the separation between fluorescent screen and light sensitive coating is sumciently large to cause excessive diffusion of light passing therethrough. Where the developed image of the cathode ray tube luminous trace is blurred somewhat by passage through a thick glass wall, it is still possible to obtain accurate marking by inking the center of such trace. This, however, is a, tedious process not too well adapted to mass production techniques.

The present invention contemplates and has as a primary object the provision of novel means and procedures for providing individual electron tube markings. In accordance with the principles of this invention, a cathode ray or like electron tube is individually marked by exposing a light sensitized surface thereof to a recorded image of the desired markings, this image bearing a predetermined relationship to the movement of electrons within the tube.

In one form of the invention, a cathode ray tube is supported in fixed, spaced relation with a camera and a predetermined deflection and intensity pattern of theluminous spot is photographed thereby. The face of the cathod ray 3 tube is then sensitized, and an image of the luminous spot deflection pattern, as photographically recorded, is projected or otherwise impinged upon th sensitized surface in precise registration with the original luminous pattern 1 is to provide means for individually marking cathode ray tubes of all sizes with sharply defined lines related to the movement of the oathode ray tube trace.

These and other objects of the present inven tion will now become apparent from the following detailed specification when taken in connection with the accompanying drawings in which:

Fig. l is a general view of apparatus utilized for photographing a cathode ray tube luminous trace;

Fig. 2 is a view of a representativ negative.

obtainable with the apparatus of Fig. 1;

Fig. 3 illustrates the appearance of the negative in Fig. 2 following reversal;

Fig. 4 is a perspective view, partly in section, illustrating a step in th process of cathode ray tube marking as disclosed herein;

Fig. 5 is a general View of the apparatus of Fig. 1, modified for the purpose of impinging an image upon a cathode ray tube;

Fig. 6 is a general perspective view of a calibrated cathode ray tube;

Fig. '7 is a fragmentary perspective view, partly in section, illustrating the structural details of the face of the cathoderay tube of Fig. 6; and

Fig. 8 is a fragmentary perspective view of a cathode ray tube such as is shown in Fig. 6, but with markings thereon for special radar application.

With reference now to the drawings, and more particularly to Fig. 1 thereof, there is illustrated apparatus for forming and photographically recording an image appearing upon the face of a cathode ray tube l l of the electrostatic deflection type. Basically, this apparatus comprises a long, cast metal frame 12, similar to the bed of a lathe or like machine tool, formed with a longitudinal slot (not shown) and adapted to support oppositely disposed, longitudinally slidable standards (3 and [4.

Standard l3 comprises a metal casting having integrally formed base members l5 and [6 which, subsequent to longitudinal adjustment along bed (2, may be releasably secured by clamps IT and 18, respectively. Extending upward from stand ard i3 are integral supports 21 and 22 to which a metallic cathode ray tube shield and support 23 is rigidly fastened.

As shown, metallic shield 23 comprises a substantially conical section extending and flaring outwardly from an integral cylindrical section. Shield 23 thereby conforms to the outline of cathode ray tube ii. The left-hand end of supporting shield 23, as viewed in Fig. 1, is sealed by a securely attached cylindrical cap 24 which, in turn, encloses a suitable cathode ray tube connecting socket Thephysical relationship of connecting socket '25 and supporting shield 23 is fixed a plurality of screws 26 extending into socket 25 through cap 24. Electrical connection to cathode ray tube H is made through a connector 27 and a flexible cable 3| extending therefrom through cap 24 into socket 25; the latter element engaging the connecting pins extending from tube base 33.

In the conventional manner, the base 33 of cathode ray tube ii and socket 25 are formed with mating key and keyway, respectively (not shown). The position of cathode ray tube H with respect to frame [2 is consequently uniquely determined, and will not be changed by repeated insertion and withdrawal. For a cathode ray tube which does not utilize a key for fixing the relative position of insertion in a connecting socket, other suitable position determining apparatus may, of course, be provided.

The electrode system for generating and deflecting an electron beam within tube l I has been schematically illustrated, and comprises an indirectly heated cathode 34, followed axially by an intensity control grid 35, focussing and accelerating electrodes 38 and 31, respectively, and orthogonal (horizontal and vertical) deflection plates 33. For reasons of clarity, electrical wiring to these electrodes has been shown in Fig. l as extending directly through the wall of the tube. An electromagnetic deflection type tube is in most respects structurally similar; however, or hogonal deflection plates 38 are replaced by orthogonal deflection coils affixed externally of the tube. Supporting shield 23, which also functions to preclude interference by stray fields, may be readily modified for application of this invention to electromagnetically deflected cathode ray tubes.

The inner face of cathode ray tube H is uniformly covered with a fluorescent phosphor 4| generating a luminous spot upon the impact of the tube electron beam, schematically represented by. broken line;

Deflection. of the electron beam and simultaneous control of the intensity thereof produce the desired image upon the phosphor.

For marking the face of cathode ray tube ll, connection is made to an energizing circuit which, in general, comprises a power source for applying normal operating potentials to the tube and means for sweeping the beam in a predetermined intensity and delection pattern. In Fig. l, a calibrating circuit for cathode ray tube II has been shown in block form as a power source 43 for the electrodes of the tube electron gun, and a deflection signal source 44 for energizing deflection plates 38. Deflection signal source 44 is coupled to power supply 43 for purposes of obtaining suitable operating potentials therefor.

To provide cathode ray tube II with an individual orthogonal coordinate system, power supply 43 and deflection signal source 44 may be arranged and connected to the tube electrodes in the manner fully disclosed in the aforementioned patent. Such arrangement results in deflection of electron beam 42 to form a uniform, luminous, linear trace, and deflection of this trace in equipotential steps in mutually perpendicular directions. Throughout the deflection period, the electron beam intensity is controlled by application of suitable blankingsignals to control grid 35. Inasmuch as the details of the cathode ray tube energizing circuit are not critical to an understanding of the present disclosure, further discussion thereof is deemed unessential at this point.

standard l4 supports, as illustrated in Fig. 1, means for photographing the luminous pattern presented upon fluorescent screen 4| of cathode ray tube H. Basically, standard l4 comprises a base member 45 adapted for longitudinal motion along frame l2 and a clamp 41 for releasably locking this member. Afiixed to the upper portion of standard I4 is a conventional mechanical feed which includes a table and a feed screw 5| disposed axially of the bed l2, and driven by adjusting hand wheel 52. This feed screw engages slide 53 and thus, rotation of hand wheel 52 results in axial movement of slide 53.

A camera 54 is positioned upon slid 53 and arranged whereby the optical axis thereof coincides precisely with the longitudinal axis of cathode ray tube obtain fine adjustment of the axial spacing between the screen 4l of cathode ray tube II and the focal plane of camera 54.

In practical application of this invention, it is preferable that camera 54 be of the 35 mm. or 70 mm. type adapted to permit a considerable number of exposures for each film loading. In order to minimize distortion and thereby increase the accuracy of the markings provided for cathode ray tube H, bed I2 should be of sufficient length to permit the utilization of a comparatively long focus lens for camera 54. In this manner the angle a subtended by fluorescent screen 4| of cathode ray tube H, is maintained at a desirable small value.

To mark the face of cathode ray tube II with the apparatus illustrated in Fig. 1, the tube is inserted into supporting shield 23. The axial spacing between fluorescent screen 4| and the focal plane of the camera 54 is then set by adjustment of the spacing of standards l3 and I4. Fine adjustment of this separation may be made by handwheel 52.

Camera 54 is then focussed upon fluorescent screen 4| through the glass envelope of cathode Hand wheel 52 is employed to ray tube At this point, cathode ray tube H is energized from power supply 43 and deflection signal source 44 so that its electron beam will sweep out a luminous pattern of the desired form upon fluorescent screen 4|. The entire apparatus is operated in a dark room so that camera 54 only records the luminous pattern.

The nature of the exposure required by the film in camera 54 will be dependent upon the nature of the particular luminous configuration being photographed. Thus, if substantially automatic calibration means are employed to sweep the electron beam in the manner described in the aforementioned patent application, the camera shutter may be set for Time and the entire pattern recorded during a single exposure. As described in the aforementioned patent, the electron beam may be blanked during periods of trace movement, and accordingly, only distinct lines will be photographed. Blanking means, however, need not be employed to render the trace invisible during periods of motion between fixed, visible steps thereof, since the shutter of camera 54 may be closed while the trace is being properly positioned upon the fluorescent screen and opened thereafter for the time required to expose the film. Operation of the camera shutter and the deflection signal source 44 may be readily synchronized electrically or mechanically.

A large number of tubes may be photographed in sequence upon one strip of film. It is, of course, essential that each exposure on the film strip be identified in relation to the cathode ray tube screen photographed.

Subsequent to exposure, the film is removed from camera 54 and developed. With reference now to Fig. 2 there is illustrated a developed film section 5| containing an exposure representative of a rectangular coordinate calibration of a typical cathode ray tube. The generally circular image 62 is an orthogonal grid of alternate heavy and light black lines upon a clear background. Each line of image 52 is the photographic reproduction of a linear trace of cathode ray tube H. For the image illustrated, the coordinate lines are separated by spaces representing the deflection caused by a predetermined change of deflection potential. Alternate light and dark lines are obtained, in accordance with the principle disclosed in the aforementioned patent, of correspondingly varying the trace intensity as it is displaced across the face of the tube.

For reasons which will become apparent upon further consideration of this disclosure, the image on film section is then reversed. Reversal may be accomplished directly during the development of film section (5| or by contact printing upon another film section subsequent to development. Film section 6i, as reversed, is illustrated in Fig. 3; and the reversed image 63 comprises a grid of white lines upon a dark field.

After the luminous pattern appearing on screen 4| has been photographed, a described above, cathode ray tube is removed from the apparatus of Fig. l, and the outer face thereof filmed with an adhering light sensitive substance, preferably in the form of a silver halide emulsion as used for photographic plates. The filming process is comparatively simple and may be accomplished on a reduced scale in the manner illustrated in Fig. i. In this figure, cathode ray tube H is shown partially immersed in liquid sensitive emulsion B4 within vessel 55. The

accuse:

depth of immersion need only be sufficient to coat the outer surface of theglass face 15 to .the

circular bounding edge of the fluorescent screen 4| (Fig. 1).

prior to immersion in the light sensitive substance B l. To eliminate air bubbles-and to obtain a uniform film, the tube l l is rotated duringimmersion as shown in Fig. 4.

carried out under lighting conditionsconsistent with the nature of the sensitive materialv 64..

Preferably, the applied emulsion is of high contrast, non-panchromatic type so-thatiit may be.

as recorded in photographic film 6|, upon the sensitizes. face of cathode ray tube H in precise register with the original luminous pattern formed upon fluorescent screen-4i. Essentially, the apparatus illustrated in Fig. 5 is that described in connection with" Fig. l for exposing film 6i, with the exception that no circuit connections are made to cathode ray tube- H and that camera 55 is replaced by projector =51. Thus, cathode ray tube ll, filmed as described in connection with Fig. 4, is inserted within the conductive shield 23 so that its connecting pins are engaged within socket 25 (not shown in Fig. 5). The key and lreyway arrangement described above, insure'that the relative position of cathode ray tube ll, when set for image projection as in Fig. 5, is precisely the same as when inserted for photographing in Fig. 1.

Projector Si is supported upon standard [4 so that its optical axis is coincident with the longi-- tudinal axis of cathode ray tube ll. Preferably, lens focal lengths and lens to tube distances are equal in Figs. 1 and 5. Accordingly, the angle a subended by the face of cathode ray tube H in 5 equals that shown in Fig. 1.

Film section bearing the reversed image 63 illustrated in Pi". 3, is inserted into a negative carrier ll hich properly positions the film during projection. The projected image-l2 is sharply focussed so that distinct lines are obtained upon the filmed tube screen, and these lines, because of the reciprocal arrangement of camera and projector (Figs. 1 and 5), are in exact registration with the original luminous lines photographed. Luminous registration mark rs (not shown) extending radially from shield 23 may be employed to simplify the registration problem.

Subsequent to exposure in the apparatus-of Fig. 5, the sensitized outer surface of the cathode ray tube 1 l is processed. The processing required is a function of the type of coating material utilized. For the conventional photographic emulsion, processing includes the steps of development, rinsing and fixing. This may be carried out in a manner similar to that disclosed in connection with l, except that liquid emulsion Ed is successively replaced by the required developer, rinse and fixer. It is preferable that development be carried out for' a" comparatively A transparent base coat, such-as collodion, may of course be appliedtozthe glass It is, of course. evident that the operation depicted in Fig. 4.is

When dry, the-face of the.

short time-in ahigh contrast'developer toprovide a distinct marking. Fixing of the sensitive film is followed by a final rinse and drying. At this point the cathode ray tube is complete with fixed, individual markings of a coordinate system conforming to the surface of the glass face of the tube. The processed photographic emulsion may be protectedby a suitable coating of varnish, or the like.

In Fig. 6, cathode ray tube H is illustrated completewith calibrated and processed film 13. Since the reversedimage 63 (Fig. 3) was projected, the scale comprises a grid of black lines upon a transparent field. Fig. 7, which i a fragmentary perspective view of cathode ray tube l l, illustrates in section, the'composite tube face structure; namely, fluorescent screendl, glass envelope (5,: and the adhering processed photo-- graphic coating, "F3.

The rectangular coordinate; system of lines.

shown upon the face of cathode ray tube H in Figs. 6 and '7 provides accurate means for studying signal waveforms. It is emphasized that due to the variation of the deflection sensitivity over the screen surface, the physical spacing between lines of coordinate system will not necessarily be uniform. However, the space between two adjacent lines is truly representative of a predetermined deflection potential and is -inde pendent of the variable physical spacing therebetween.

This result is obtained because the space between lines represents a fixed deflection potential. A tube marked by means of the apparatus illustrated in Figs; 1 and 5 is literally custom calibrated. Parallax errors are reduced substantially'as a result of theuniform proximate relation between the processed photographic layer 13 and the fluorescent screen M.

The broad principle hereinabove disclosed may be utilized as a basis for obtaining a cathode ray tube marking of any desired form. Thus, the deflection signal source 44 illustrated in Fig. 1 may beemployed to provide for a luminous tracedefiection and intensity pattern corresponding to signals typical of those observed upon the oath-- Ode-ray tube in its ultimate application.

Fig. 8 is a fragmentary view of a cathode ray tube ll of the type which may be employed in a radar plan position indicator. A map 72 of the surrounding terrain and circular range markers, as actually recorded by the tube ll when in radar use, is shown over the tube face. has been-prepared in accordance with the steps outlined above for applying a coordinate scale. For radar purposes, the density is controlled so that the developed image illustrated in Fig. 8 contains no deep blacks, and thus, target echoes appearing upon the fluorescent screen while in actual operation will at all points be visible through-the photographic reproduction. When the plan position indicator type cathode ray tube shown in Fig. 8 is employed for moving target indication; only targets in motion will appear upon the face or" the tube and these will be presented in relation to the terrain marked upon the face of the tube.

For television test purposes, the cathode ray tube may be photographically marked in accordance with a test patern. This pattern may be generated and photographed in the apparatus illustrated in Fig. l, and projected upon the oathode ray tube in the apparatus illustrated in Fig. 5;

It is thus apparent that' numerous modifica- The map 13 l tions and extensions of the principles herein disclosed may become evident to those skilled in the art. Accordingly, it is preferred that the scope of this invention be limited solely by the spirit of the appended claims.

The invention disclosed herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalty thereon or therefor.

What is claimed is:

1. The method of applying predetermined markings to a cathode ray tube which comprises the steps of presenting a luminous image upon said tube, preparing a substantially permanent photographic record of said image apart from said cathode ray tube and photographically processing a reproduction of at least a portion of said separate photographic record upon said tube.

2. The method of applying predetermined markings to a cathode ray tube which comprises the steps of energizing said cathode ray tube to present a luminous image having the configuration of the aforesaid markings, preparing a photographic record of said luminous image, applying a sensitive substance to said cathode ray tube and photographically processing a reproduction of said photographic record into said sensitive substance.

.3. The method of applying predetermined markings to a cathode ray tube which comprises the steps of energizing said cathode ray tube to present a luminous image having the configuration of the aforesaid 'markings, preparing a photographic record of said luminous image, applying a sensitive substance to said cathode ray tube and photographically processing a reproduction of said photographic record into said sensitive substance in register effectively with said luminous image.

4. The method of marking a cathode ray tube having a fluorescent screen, which comprises the steps of energizing said cathode ray tube to present a predetermined luminous pattern upon said screen, preparing a photographic record of said luminous pattern, applying a sensitive coating to said cathode ray tube in proximate relation with said fluorescent screen and impinging a luminous image of said photographic record of said pattern upon said coating in register effectively with the position of the aforesaid luminous pattern upon said fluorescent screen.

5. The method of marking a cathode ray tube having a fluorescent screen, which comprises the steps of energizing said cathode ray tube to present a predetermined luminous pattern upon said screen, preparing a photographic record of said luminous pattern, applying a sensitive coating to said cathode ray tube in proximate relation with said fluorescent screen, impinging a luminous image of said photographic record of said pattern upon said coating in register effectively with the position of the aforesaid luminous pattern upon said fluorescent screen, and processing said sensitive coating to provide substantially permanent markings in proximate relation with said fluorescent screen.

6. The method of marking a cathode ray tube having a fluorescent screen and means adapted to produce a luminous spot thereon, which comprises the steps of energizing said cathode ray tube and sweeping said luminous spot in a predetermined deflection and intensity pattern, preparing a photograph of at ieast a portion of said spot deflection and intensity pattern, applying a light sensitive substance to said cathode ray tube in proximate relation with said fluorescent screen, projecting a luminous image of said pat tern from said photograph upon said sensitive substance, the relative position of said luminous image upon said substance during projection overlying and corresponding with the position 00- cupied by said pattern upon said fluorescent screen, and developing and fixing said sensitive substance.

'7. The method of substantially permanently marking the face of a cathode ray tube having a fluorescent screen, which comprises the steps of energizing said cathode ray tube with substantially normal operating potentials to provide a luminous spot on said fluorescent screen, exposing a film within a camera to light from said spot, deflecting said luminous spot, developing said film to provide an image of the pattern traced by said spot on said fluorescent screen, applying a light sensitive photographic emulsion to said face of said cathode ray tube in proximate relation with said fluorescent screen, projecting a luminous image of said developed film upon said sensitive emulsion in register effectively with the luminous image upon said fluorescent screen initially photographed with said camera, thereby exposing said emulsion, and developing and fixing said exposed emulsion to provide markings adjacent to said fluorescent screen and bearing a relation to the deflection of the luminous spot of said cathode ray tube. r

8. The method of claim 7, and including the step of photographically reversing said developed film prior to projection upon said sensitive emulsion, whereby the markings corresponding to the movement of said spot as developed in said exposed sensitive emulsion are dark upon a substantially transparent field.

9. The method of marking the face of a cathode ray tube having a. fluorescent screen, which comprises the steps of applying a sensitive substance to said tube adjacent to said screen and impinging a luminous image upon said substance from without said tube.

10. The method of applying predetermined markings to a cathode ray tube having a fluorescent screen which comprises the steps of preparing a photographic film having an image of said markings, covering said tube adjacent said screen With a sensitive substance, projecting said film image upon said sensitive substance and processing said sensitive substance.

11. The method of applying markings to a cathode ray tube bearing a relation to luminous images on said tube during normal operation thereof, which comprises the steps of normally energizing said cathode ray tube to present a luminous image, photographing said luminous image to provide a record thereof and processing record of said image upon said cathode ray tube in predetermined relation to the position of said luminous image when photographed.

12. The method of marking a rectangular coordinate system of lines upon the face of a cathode ray tube, which comprises the steps of energizing said cathode ray tube with substantially normal operating potentials to provide a luminous spot on said tube face, sweeping said spot in a first direction while deflecting said spot in distinct steps in a second direction perpendicular to said first direction, sweeping said spot in said second direction while deflecting said spot in distinct steps in said first direction, blanking said spot during each of said distinct deflecting steps,

thereby presenting a grid of luminous lines upon saidtube face, exposing a film within-a camera to said grid of lines, processing said'fllm, applying a light sensitive emulsion to the face of said cathode ray tube, projecting a focussed luminous image of said film upon said emulsion to expose said emulsion and developing and fixing -said sensitive emulsion.

13. Apparatus for marking a cathode ray tube comprising, means for energizing said cathode raytube to display an image to berecorded, means for photographing said cathode ray tube, means for securely supporting said cathode ray tube and said photographing means in predetermined spaced relationship, an image projector, said lastmentioned means being arranged to support said cathode ray tube and said image projector insaid predetermined spaced relationship.

14. The method of applying predetermined markings to the face of a cathode ray tube having a fluorescent screen, which comprises the steps of preparinga record of said markings, sensitizing said cathode ray tube ina region in proximate relation with said fluorescent screen, impinging a luminous image of said markings from said record upon the region so sensitized from Without said cathode ray tube and processing said sensitized region.

15. The method of applying predetermined markings to the face of a cathode ray tube having a fluorescent screen, which comprises the steps of preparing a substantially permanent photographic record of said markings, photographically sensitizing the face of said cathode ray tube in a region in proximate relation with said fluorescent screen, exposing the region so sensitized to a luminous image of said photographic record, and photographically processing said sensitized region.

16. The method of-applyingto-theface of a cathode ray tube markings bearing apredetermined relation-to images presentablegon said tube during normal operation thereof which comprises the steps of preparing a record of said markings, applying a sensitive substance tosaid tube, impinging from without said'cathode ray tube and from said record an image of said markings upon said sensitive substance, and processing said sensitive substance.

17. Apparatus for marking a'cathode raytube comprising astructural framework. means upon said framework for releasably and. nonrotatably supporting a. cathode ray tube inapredetermined position, means for photographingsaidcathode ray tube, means upon said framework for supporting said photographing means on the longitudinal axis of said cathode ray tube, an image projector, said last-mentioned means being arranged to support said image projector on said axis for projection upon said cathode ray-tube. of an image recorded by said photographing means. 18. Apparatus for processing markings upon the face of acathode ray tube in proximate, relation with the fluorescent screen thereof comprising, av structural framework. an, electrical connection socket secured to said framework for receiving said cathode ray tube, means for fixing the relative positionv of said cathode. ray tube with respect to said framework, a camera, an image projector, means on said framework for alternatively supporting. said camera and said image projector .onrthe longitudinalaxis of said cathode ray tube in spaced'relationship therewith.

JOSEPH WEINGARTEN.

References Cited in the, file of this patent UNITED STATES PATENTS Number Name Date 1,818,760 Selenyi Aug. 11, 1931 2,152,487 Knoll Mar. 28, 1939 2,176,225 Ogloblinsky Oct. 1'7, 1939 2,186,268 Pakala Jan. 9, 1940 2,195,444 Brett Apr. 2, 1940 2,241,809 De Forest May 13, 1941 2,251,984 Cleaver et a1 Aug. 12, 1941 2,292,045 Burnett Aug. 4, 1942 2,294,015 Salb et a1 Aug. 25, 1942 2,330,604 Messner, Sept. 28, 1943 2,428,427 Loughren Oct. 7, 1947 2,446,674 Sproul..- Aug. 10, 1948 2,449,093 Weingarten. a--- Sept. 14,1948 2,449,752. Ross Sept. 21, 1948 2,457,744 Sturm "1 Dec. 28, 1948 2,462,263 Haynes Feb. 22, 1949 2,483,147 Mol. Sept. 27,1949

FOREIGN PATENTS Number Country Date 591,856 Great Britain Sept. 1, 1947