US3387160A - Mounting means for moving shadow mask axially forward upon heating - Google Patents

Description

June 1968 J. w. SCHWARTZ 7,

MOUNTING MEANS FOR MOVING SHADOW MASK AXIALLY FORWARD UPON HEATING Filed Jan. 11, 1967 INVENTOR:

JAMES W. SCHWARTZ United States Patent MOUNTING MEANS FOR MOVING SHADOW MASK AXIALLY FORWARD UPON HEATING James W. Schwartz, Western Springs, Ill., assignor to National Video Corporation, Chicago, R1,, at corporation of Illinois Filed Jan. 11, 1967, Ser. No. 608,561 3 Claims. (Cl. 313-85) ABSTRACT OF THE DISCLOSURE A quadrilateral shaped fitting for mounting a mask in a color television tube, the fitting being adapted to be distorted upon increase in dimension of the shadow mask relative to the tube envelope so as to produce an axial movement of the shadow mask and thereby maintain the mask openings in register with electron beams.

Summary of invention The usual color television tube making use of triads of green, red and blue dots, has a shadow mask interposed in the electron beam path closely adjacent the phosphor screen. Such a mask can change in dimension relative to the usual glass envelope of the tube, particularly because of increase of temperature, and this repositions the abovementioned openings laterally of their original positionsthereby bringing about a degree of misregister. I have solved this problem by providing true compensation for'a change in size of the mask relative to the envelope and implement this through using a parallelogram-like connection between the mask and the envelope which partially collapses on itself in a pivotal-type movement so as to reposition the mask closer to the phosphor screen and thereby maintains the mask openings in register with the electron beams.

The invention is described in conjunction with an illustrative embodiment in the accompanying drawing, in which- FIG. 1 is a fragmentary sectional view of a portion of a color television tube showing the shadow mask mounted within the face plate;

FIG. 2 is a fragmentary sectional view of a portion of a tube, essentially that seen in FIG. 1, but enlarged relative thereto and parts thereof in a somewhat dilferent operational condition;

3,387,160 Patented June 4, 1968 opening of the spring clip 14. In the inventive arrangement, the opening 17 receives a portion of the post 12 and provides the actual mounting of the mask on the face plate. However, as can be seen in FIG. 1, the opening 15 is concentric with the post 12 and is adapted to engage a cylindrical portion 12a of the post 12 to provide an additional mounting during times of extraordinary stress. If, for example, the tube is given a rough shock so as to unduly flex the fitting 16, the opening 15 provides a sup- FIG. 3 is a fragmentary perspective exploded view of the tube parts seen in the foregoing views; and

FIG. 4 is an enlarged fragmentary perspective view of the lefthand portion of FIG. 3.

In the illustration given and with reference to FIG. 1, the numeral 10 designates generally the glass envelope portion of a color television tube. More particularly, the envelope is seen in its face-plate portion which terminates at a lip 11 (see the upper righthand portion of FIG. 1). The lip 11 is adapted to be fused to the funnel portion of the cathode ray tube (not shown). The face plate is equipped with a plurality of radially inwardlyextending posts as at 12 in FIGS. 1-3 and these are provided for mounting the usual shadow mask 13.

Normally, the shadow mask 13 is supported on the posts 12 by means of spring clips 14 which are weldably plemental engagement means with the posts 12 to additionally stabilize the mask 13 in place within the tube 10.

The fitting 16 is constructed of relatively light metal (in comparison with the spring clip 14) and is seen to include a main body portion or panel 18 about the opening 17 integrally coupled to laterally-extending legs 19 and 21, the legs 19 and 21 in turn being equipped with integral flanges as at 20 and 22 which are weldably secured to the associated spring clip 14. The spring clip 14 is equipped with an abutment means in the form of boss or projection 23 which is adapted to engage a confronting surface of the mask 13.

Operation The operation of the invention can be best understood from a comparison of FIGS. 1 and 2. In FIG. 2, the numerals applied to parts whose position has changed from that in FIG. 1, are differentiated from the corresponding numerals in FIG. 1 by the addition of a prime Thus, for example, the shadow mask is designated 13' in FIG. 2 and it will be seen that the mask 13' is somewhat closer to the envelope 10 in FIG. 2 than it was in FIG. 1 (taking into account the difference in scale). Normally, this occurs because the heatup of the mask 13 is greater than that of the envelope 10. For example, the shadow mask may increase in temperature about 30 C. while the glass envelope 10 increases only 10 C. in normal operation. The lateral expansion of the mask 13 (to the condition designated 13' in FIG. 2) brings the frame 24 of the mask into engagement with the inner end of the abutment 23 (as can be appreciated from the designations 23 and 24' in FIG. 2). The engagement of the abutment 23 with the mask 13 results in partially collapsing or distorting the fitting to that shown at 16' in FIG. 2, particularly in the area designated 25.

It will be seen that the main body portion 18 is related to the connective portion 19 by a smaller acute angle in FIG. 2 as compared to that in FIG. 1. Thus the quadrilateral originally defined by the spring 14, legs 19 and 21, and body portion 18 is partially collapsed or deformed to that shown in FIG. 2 and defined by the parts 14', 19' and 21, and 18' respectively.

It will be appreciated that the movements encountered and employed are of a relatively small order of magnitude. The expansion of the shadow mask is in terms of a few thousandths of an inch and to compensate for this lateral movement, it is only necessary to advance the mask axially toward the phosphor screen a correspondingly small distance. A more detailed explanation and showing of this activity can be seen in the co-owned, co-pend ing application of James W. Schwartz and Laslo Javorik Color Television Tube Mask Mounting.

It will be appreciated that the inventive construction provides a truly selective repositioning of the shadow mask 13 axially of the tube in contrast to other techniques which are temperature-dependent. Although the inventive construction does respond to changes of temperature interiorally of the tube, such changes can be eifective to reposition the mask only if these temperature changes result in a change in size of the mask relative to the envelope. If, for example, the envelope were to change in size correspondingly, no movement .of the mask would occur when the inventive construction is employed. On the other hand, constructing the mounting of temperatureresponsive materials could result in a repositioning of the mask when none is desired, i.e., where the original relationship between the mask and the screen is preserved, notwithstanding change in size.

By providing the generally cylindrical portion 12a of the post 12, I insure that upon contact of the spring clip 14 (in the area of the opening 15) with the post 12, there is a firm seating against any extraordinary stress which might tend to otherwise dislodge the mask from its proper mounting on the associated posts.

While in the foregoing specification a detailed descrip tion of an embodiment of the invention has been set down for the purpose of explanation, many variations of the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

1 claim:

1. A color television tube comprising an elongated envelope with an enlarged faceplate panel at one end and a phosphor pattern deposited on the interior of said faceplate panel defining a viewing screen, a plurality of mounting posts embedded in a peripheral flange of said faceplate panel and extending radially of said tube, an apertured shadow mask, a frame about said mask of rigidly supporting the same, resilient mounting means on aid frame for each of said posts adapted for limited movement inward of said frame, a distortable member having first and second legs attached to said resilient means and inclined outwardly and rearwardly therefrom, and a panel integral with said legs and having an aperture for receiving an associated post, whereby as said mask and frame expand laterally due to heating, said resilient means is compressed until limited, so that additional expansion causes further inclination of said leg members, thereby translating said mask forward.

2. The structure of claim 1 wherein each of said resilient means comprises a resilient, fiat mounting spring attached to said frame and defining an aperture in line with the aperture of its associated distortable member for also receiving its associated post; and an abutment mounted between said frame and said spring for limiting inward motion of said spring.

3. The structure of claim 2 in which said distortable member has two legs thereof arranged generally parallel to each other with the panel interconnecting said legs and the edges of said legs remote from said panel being coupled to said resilient means, whereby a generally parallelogram shape is provided, an opening in said panel receiving said post for mounting said mask thereon, the angular relation between said panel and said legs being variable to reposition said mask axially of said tube.

References Cited UNITED STATES PATENTS 2,795,718 6/1957 Van Hekken et al. 3,330,980 7/1967 Shrader.

ROBERT SEGAL, Primary Examiner.

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