US3397336A - Target rotatable by tubular member of deformable, shape-retaining material - Google Patents

Description

Aug. 13, 1968 w. c. DAVIS T TARGET ROTATABLE BY TUBULAR MEMBER OF DEFORMABLE, SHAPE-RETAINING MATERIAL Filed March 6, 1967 2 Sheets-Sheet 1 INVENTORS WARREN 6. DAVIS 8 2 1 1 a 2 J 2 m :1 F 2 m 2 m R I m W7) I NH Aug. 13, 1968 w. c, DAVIS ETAL TARGET ROTATABLEI BY TUBULAR MEMBER OF DEFORMABLE, SHAPE-RETAINING MATERIAL Filed March 1967 2 Sheets-Sheet 2 ABCDEFG /V V E /V T 0R5 WA RIPE/V 6. 0A V/S GO/RDO/V R. SPENCER AGE 7' United States Patent TARGET ROTATABLE BY TUBULAR MEMBER OF DEFORMABLE, SHAPE-RETAINING MATERIAL- Warren C. Davis, Cohasset, and Gordon R. Spencer, Westwood, Mass., assignors to Raytheon Company, Lexington, Mass., a corporation of Delaware Filed Mar. 6, 1967, Ser. No. 620,751 6 Claims. (Cl. 313146) ABSTRACT OF THE DISCLOSURE An adjustable target support for cathode ray tubes comprising a pin-like projection extending from the rear surface of a target and extending freely through an opening in the wall of the tube envelope, and a thin metal sheath fixed at one end to the envelope around the opening and enclosing the outer end portion of the projection, the sheath being secured at its other end to the outer end of the projection and being of a flexible, deformable metal capable of being twisted so as to rotate the projection and target thereon whereby the target may be adjusted with respect to an impinging electron beam trace.

Background 0 the invention In the manufacture of many types of cathode ray tubes, it becomes necessary to properly align the target with respect to an impinging scanning electron beam 50 that the beam will, during its scanning cycles, properly impinge upon selected locations of the target. This is especially true in cathode ray tubes of the type which produce output electric signals which are intended to correspond to selected characters impressed upon the target of the tube, which signals result from impingement of electrons upon the selected characters. In such tubes, the target normally consists of a disc having a relatively large number of characters arranged thereon in predetermined sequences such as spaced rows of characters. It will be apparent that the rows of characters must be aligned so that the raster of the electron beam scan will coincide therewith in such a manner that the electron beam, during successive scans, will scan along paths which are aligned substantially parallel with the rows of characters. Otherwise, if the rows of characters are arranged at an angle to the scans, the output signal will not represent a true reproduction as desired.

The prior art discloses various types of supporting structures for the targets of cathode ray tubes. The majority of such structures embody fixed and immovable supporting means which render the targets impossible to align after they have been assembled with the tube envelope. Certain supporting structures are known which provide adjustment of targets axially of the tube in a direction toward and away from the electron-producing gun.

Summary of the invention In accordance with the present invention, there is provided a structure for a cathode ray tube target which permits rotary movement of a target about a predetermined axis after the target has been assembled with the tube envelope. Such structure embodies a pin or shaft which extends from the rear side of the target through an end wall of the tube envelope. The end wall of the envelope has fixed therein a tubular member within which the shaft extends in freely movable spaced relation. The shaft is affixed to the tubular member only at the extreme outer ends thereof by a weld or other suitable means, and this constitutes the sole support for the target, other than for spring fingers or spacers which may be located between the target and the end wall in order to provide desired spacing therebetween and to retain the target in a plane normal Patented Aug. 13, 1968 to the longitudinal axis of the structure. Adjustment is accomplished in accordance with this invention by manipulation of the tubular member, which is made thin and relatively easily deformable for this purpose. It will be apparent from the following description that the tubular member may be manipulated in a twisting fashion so as to rotate the target about the longitudinal axis of the shaft. The tubular member is preferably made of metal so that when adjustment is accomplished, the member will retain its acquired shape or configuration so as to retain the target in properly adjusted position. The spacers or spring fingers at the rear of the target will, curing adjustment, slide along the inner surface of the end wall and will constantly retain the target in spaced relation therewith, preferably perpendicular to the longitudinal axis of the tube.

Brief description of the drawings FIG. 1 is a side elevational view of a cathode ray tube, partially in section, illustrating a preferred form of the invention;

FIG. 2 is an enlarged side elevational view of the target end portion of the tube illustrated in FIG. 1;

FIG. 3 is an enlarged front elevational view of a character-bearing target of a type utilized with the invention; and

FIG. 4 is an enlarged perspective rear view of a target embodying modified spacing means on the rear surface thereof.

Description of the preferred embodiments Referring more particularly to the drawings wherein like characters of reference designate like parts throughout the several views, the cathode ray tube illustrated in FIG. 1 embodies an elongated dielectric envelope 10 having integral end walls 11 and 12 there-on. Supported upon end wall 11 of the envelope 10 is an electron gun 13 adapted, upon application of suitable electrical signals, to generate an electron beam which is directed upon a target 14 located at the opposite end of the envelope 10 and supported by end wall 12 thereof. The electron gun 13 comprises the usual cathode and grid structures to be found in well-known electron gun structures and is shown in FIG. 1 as additionally including pairs of spaced deflection plates 15 which are adapted to be interconnected into the tube electrical circuitry so as to deflect the electron beam in such a manner as to produce a raster upon the target 14. The electron gun 13 and the method of its operation are well known and, therefore, will not be discussed in detail herein.

A typical target utilizable with this invention is illustrated in FIGS. 2 and 3 and comprises a first or rear disc or plate 16 having affixed to its inner surface one or a series of spacing elements 17 upon which is affixed a character-bearing disc or plate 18. Disc 18 is conveniently formed of metal, as are the spacers 17 and disc 16, and has provided thereon a thin layer 19 of aluminum. Upon the aluminum layer 19 are arranged rows 27 of characters, as shown best in FIG. 3, which characters may be in the form of alpha-numeric or other configurations and are conveniently printed thereon by the use of well-known techniques not constituting a part of this invention, the

characters preferably being of carbon or other material having a secondary emission coeflicient different from that of the aluminum layer 19.

Upon the exposed surface of rear disc 16 are soldered or otherwise fixed a number of spring fingers 20 which are adapted to 'slidably engage the inner surface of end wall 12 of the envelope for yieldably locating the target in spaced relation with said end wall and to assist in maintaining the target in a plane substantially perpendicular or normal to the longitudinal axis of the'device. Extending from the central portion of rear disc 16 is a pin, shaft, or other similar projecting member 21, which shaft 21 extends through an Opening 22 in end wall 12.. A tubular supporting member 23 also extends through said opening 22 and has one end thereof sealed to the glass of the envelope within the opening 22, as shown best in FIG. 2, the major portion thereof extending outwardly of the tube envelope. The shaft 21 extends axially through the tubular member 23 in slightly spaced relation with the inner surface of the internal bore in member 23. However, the extreme outer end portion of the shaft 21 is rigidly and securely aflixed to the extreme outer end portion of the tubular member '23, as by a weld 28 or the like, whereby the shaft and tubular member are retained in assembled relation with one another.

The tubular member 23 is formed of a glass-sealing metal, preferably chrome-iron alloy or Kovar depending upon the particular kind of glass be-ing used in the envelope, and is made relatively thin, preferably about mils in thickness. The member, therefore, is readily deformable under pressure and will retain its deformed shape without any substantial tendency to return to its initial configuration.

It will be understood that, upon operation of the tube, an electron beam will be formed by the electron gun 13 and will be directed upon the character-bearing surface 19 of the target, and will be caused, by deflection plates 15, to scan the surface of layer 19 in the manner of a raster, as is well known. The deflection plates are preassembled with respect to the gun and with respect to the remainder of the tube. However, it has been found that, in the assembly of a target within a tube envelope, the rows 27 of characters on the aluminum surface 19 will not always be perfectly aligned parallel with the scanning lines of Ithe raster produced by the electron beam. Therefore, rotary adjustment of the target about its geometric center must be provided so that the proper alignment will be achieved bet-ween the rows 27 and the deflection plates 15. This is accomplished in the present invention by manually manipulating the flexible tubular member 23 by use of a suitable tool, the tubular member being twisted or otherwise deformed so as to rotate the shaft 21 and target 14 about the longitudinal axis of the shaft or about the center of the target. Such rotation of the target may be readily accomplished with the supporting structure described, and the target may be rotated in either direction for a distance of 10 or more. Such adjustment is accomplished entirely externally of the tube and can be performed once or any number of times necessary to align the target, or more specifically the rows of characters thereon, with respect to the lines of scan produced by the electron gun.

As the adjustment is being accomplished, the spring fingers upon the rear of the target will slide over the inner surface of the end wall 12 and will constantly retain the target in the desired plane and in yieldable spaced relation with the end wall 12, the fingers being provided with specially shaped end portions to facilitate such movement.

In a modified version of the target structure, there is shown in FIG. 4 a rear disc 25 of a target which is provided with rearwardly struck lugs 26 or similar projections, which lugs are adapted to extend toward the end wall 12 at an angle thereto, with the outer ends thereof engaging the wall 12 so as to properly resiliently locate the target thereagainst. Such a structure enables the rear disc 25 to be simply formed by a stamping operation, thereby eliminating the necessity to separately fabricate and assemble the spring fingers therewith, as shown in FIGS. 1 and 2.

It will be apparent from the foregoing description that, in accordance with this invention, a novel structure has been achieved which permits rotary adjustment of a target within an electron tube of the cathode ray type, which adjustment may be entirely performed externally of the tube after the tube has been completely assembled. In fact, such adjustment of a target may be achieved at any time after assembly of the tube, even at a time when the tube has been installed and operated. It is to be under stood that various modifications and changes in the structure shown and described may be made by those skilled in the art without departing from the spirit of the invention as expressed in the accompanying claims.

We claim:

1. A cathode ray tube comprising an envelope, and electron gun supported Within the envelope for generating a beam of electrons, a target within the envelope and spaced from said gun for receiving said electrons, means for deflecting said electron beam along at least one predetermined path, and supporting means for the target comprising a tubular member mounted in a wall of the envelope and projecting outwardly thereof, a shaft affixed at one end to the surface of the target remote from the electron gun, said shaft extending freely coaxially within the tubular member and having its opposite end portion affixed to the outer end portion of the tubular member and supported thereby, said tubular member being of deformable, shape-retaining material whereby twisting manipulation thereof will cause rotary movement of the shaft and consequent adjustment of the target.

2. A cathode ray tube as set forth in claim 1 wherein said target bears rows of characters thereon on its surface nearest the electron gun, and said adjustment effects alignment of said rows with respect to said predetermined path of the electron beam.

3. A cathode ray tube as set forth in claim 1 wherein spacing means are provided on the target for spacing the target from said wall of the envelope, said spacing means being slidable upon said wall during adjustment of the target.

4. A cathode ray tube as set forth in claim 3 wherein said spacing means are flexible.

5. A cathode ray tube as set forth in claim 3 wherein said spacing means are rigid.

6. A cathode ray tube as set forth in claim 1 wherein said shaft and tubular member are welded together.

References Cited UNITED STATES PATENTS 2,408,287 9/1946 Bachman 313-148 X 2,435,316 2/1948 Larson 313-65 2,443,237 6/1948 Gaudenzi et a1 313-148 2,527,550 10/1950 Hess 313-148 X 2,637,829 5/1953 Trad 313-146 X 2,682,620 6/1954 Sanford 313-148 X 3,167,629 1/ 1965 Cobine 200-144 3,181,021 4/1965 Day 313-68 3,201,628 8/1965 Day 313-68 ROBERT SEGAL, Primary Examiner.

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