US3404302A

US3404302A - Envelope wall with two continuous ledges for positioning and supporting aperture mask

Info

Publication number: US3404302A
Application number: US647699A
Authority: US
Inventors: William H Nicklas
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1967-06-21
Filing date: 1967-06-21
Publication date: 1968-10-01
Anticipated expiration: 1985-10-01

Description

Oct. 1, 1968 w. H. NICKLAS 3,404,302

ENVELOPE WALL WITH TWO CONTINUOUS LEDGES FOR POSITIONING AND SUPPORTING APERTURE MASK Filed June '21, 1967 unu uuu INVENTORI w LLIAM H. NICKLAS,

HIS ATTORNEY.

United States Patent 3,404,302 ENVELOPE WALL WITH TWO CONTINUOUS LEDGES FOR POSITIONING AND SUPPORT- ING APERTURE MASK William H. Nicklas, North Syracuse, N.Y., assignor to General Electric Company, a corporation of New York Filed June 21, 1967, Ser. No. 647,699 3 Claims. (Cl. 31385) ABSTRACT OF THE DISCLOSURE A support arrangement for an aperture mask including a continuous self-stiffened periphery and a number of integral male or female registry points thereabout. The support arrangement includes a pair of continuous spaced peripheral ledges molded from the interior surface of the tube envelope, one of which ledges includes a number of male or female registry points molded therein. The aperture mask, as supported in the tube, is disposed so that the periphery thereis is in juxtaposition with said one ledge and the registry points are aligned. Tensioning means, in the form of elongated wire springs, span the ledges to firmly restrain the aperture mask from movement.

Background of invention This invention relates to aperture masks for cathoderay tubes and, more particularly, to improved means for supporting aperture masks in color television tubes.

The display screen for a color television tube is ordinarily positioned adjacent the viewing face of the tube and usualy consists of phosphorescent color emitting material. In order to properly direct electron beams from a source at the rear of the tube so that only certain electron beams strike predetermined color emitting areas on the display screen, an aperture mask is normally positioned adjacent the display screen. The aperture mask comprises a perforated sheet of material having apertures strategically positioned so that only the desired electron beams are able to pass therethrough. The aperture mask usually is supported within the tube by a supporting arrangement which spans the space between the mask periphery and the inner surface of the tube. In order to shield stray electron beams from escaping around the periphery of the mask, some known devices employ a beam shield extending around the mask periphery. Other known devices have eliminated the beam shield by extending the mask to engage directly the inner surface of the tube. In these devices various supporting and mounting arrangements have been provided to fix the mask to the tube surface.

These prior art support arrangements for such aperture masks have generally proven to be effective. However, with the production of large volumes of color television tubes, tube manufacturers are always desirous of uncovering new ways of manufacturing components, such as aperture mask supports, which will result in reduced costs, while either retaining or improving the characteristics and functions of the prior art devices.

Summary of invention It is therefore an object of this invention to provide a simple and inexpensive support arrangement for the aperture mask of a color television tube.

It is another object of this invention to provide an improved aperture mask for a color television tube and supporting arrangement therefor which shields stray electron beams from escaping around the periphery thereof.

In accordance with one aspect of the invention, I provide a cathode ray tube including an envelope therefor,

and a pair of continuous peripheral ledges molded from the interior surface of the tube envelope. An aperture mask is provided having a peripheral surface formed to be self-stiffening and includes a number of integral registry points along the self-stiffened periphery that mate with registry points molded in one of the ledges. After the aperture mask is positioned so that the self-stiffened periphery bears upon this ledge, and after the registry points are aligned, a number of springs which span the ledges are periodicaly positioned thereabout so as to firmly trap the aperture mask against the adjacent ledge. The cooperation of the continuous ledges and the aperture mask serves also to effectively shield any electron beams which might escape around the periphery of the aperture mask.

Detailed description Other objects and advantages of the invention may better be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a view of the support arrangement of the invention in a cathode-ray tube having a portion of the envelope broken away;

FIGURE 2 is a perspective view of the aperture mask of the present invention; and

FIGURE 3 is an enlarged view of a portion of the support arrangement taken along line 3-3 of FIGURE 1.

FIGURE 1 shows a television tube comprising an envelope 1 having a funnel section 2 and a face panel section 3. The face panel section and the funnel section are joined together by means of a peripheral frit member 4. The funnel section 2 includes a flared portion 5 and a neck portion 6 wherein is disposed a source 7 for generating electron beams. The face panel section 3 includes a face plate portion 8 and a skirt portion 9. A phosphorescent color emitting display screen 10 is disposed adjacent the interior surface of the face plate portion 8 of the face panel section 3.

An aperture mask 11, best seen in FIGURE 2, is provided between the source of electron beams 7 and the display screen 10. The aperture mask 11 comprises a perforated sheet of metal having apertures 12 strategically positioned so that only certain electron beams pass there through and onto the display screen 10. The aperture mask 11 includes an outer peripheral surface 13 which is non-perforated and which is formed to be self-stiffening. By self-stiffening, it is meant that the periphery '13 is so formed that it attains a strength and rigidity beyond what it normally may possess. In this particular embodiment the mask 11 is self-stiffened by deforming the periphery 13 in somewhat sinusoidal fashion. Such deformation results in a channel 14 of greater rigidity being formed close to the perforated portion of the mask 11, a fiat portion 16 extending from the channel 14 and a downturned flange portion 17. Note that the non-perforated nature of the periphery 13 allows it to serve as a shield to prevent overscanned electrons which strike the edge of the mask 11 from leaking through to the screen.

The aperture mask 11 is mounted in the envelope 1 through the utilization of applicants novel support arrangement. The skirt portion 9 of the faceplate section 8 includes a first molded-in continuous annular ledge 18. The ledge is adapted to receive in juxtaposition the flat portion 16 of the peripheral surface 13 of the aperture mask 11 for mounting purposes. The funnel section 2 also includes anchoring means 24 comprising, preferably, a second molded-in continuous peripheral ledge 19. The anchoring'means 24 may also comprise a number of protuberances or anchor members spaced annularly around the funnel section, if desired, As is shown in FIGURE 3, the first ledge 18 also includes a number of molded-in registry points compriisng conical lands or holes or grooves to mate with registry points comprising abutment members formed into the fiat portion 16 of the mask periphery 13 so that the aperture mask 11 may be properly aligned within the envelope 1. The aperture mask 11 must be properly aligned because precise positioning of the apertures 12 in the mask 11 is essential for proper direction of the electron beams onto the display screen 10. After the aperture mask 11 has been positioned against the first ledge 18 and the

registry points

15, 20 have been properly aligned, a plurality of elongated wire springs 21 or the like are inserted to span the space between the

ledge

18 and 19, in the preferred form, to restain the aperture mask 11 from movement. One end 22 of each spring 21 rests against the funnel ledge 19 while the other end 23 of each spring 21 exerts an outward force against the mask periphery 13, thereby trapping the mask 11 against the first ledge 18 and restraining it from movement. In addition, the springs 21 provide an electrical connection between a conductive coating of the funnel section 2 and the mask 11.

The continuous molded-in ledge 18, by virtue of its continuous engagement with the periphery 13 of the aperture mask 11, serves to effectively shield any electron beams which might escape around the periphery of the aperture mask, thereby eliminating the necessity of a separate beam shield for such purpose.

Groove portions may be additionally provided in the second ledge and in the periphery of the aperture mask to firmly index the wire springs.

While the invention has been described with specificity, it is the aim of the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a cathode ray tube including a glass envelope and an aperture mask formed with a self-stilfened outer periphery, an arrangement for supporting said aperture mask within said envelope comprising:

(a) one continuous peripheral ledge molded from said envelope and disposed along the inside surface thereof;

(b) anchoring means disposed along the inside surface of said envelope and spaced from said one ledge, said anchoring means comprising a second continuous peripheral ledge molded from said envelope; and

(c) a number of tension springs which may he positioned to span the space between said one ledge and said anchoring means so as to trap the periphery of said aperture mask against said one ledge to provide an electron-impermeable seal when the periphery of said aperture mask is first placed in juxtaposition and in continuous engagement with said one ledge.

2. The supporting arrangement as recited in claim 1 wherein said self-stiffened outer periphery of said aperture mask is provided with integral spaced registry points and said one ledge is provided with integral spaced registry points, and whereby said registry points are aligned when said periphery of said aperture mask is placed in juxtaposition with said one ledge.

3. In combination, for a television cathode ray tube including a glass envelope:

(a) an aperture mask comprising a perforated portion surrounded by a continuous self-stiffened non-perforated peripheral portion;

(b) one continuous peripheral ledge molded from said envelope and disposed along the inside surface thereof;

(c) anchoring means disposed along the inside surface of said envelope and spaced from said one ledge, said anchoring means comprising a second continuous peripheral ledge molded from said envelope; and

(d) a number of tension springs which may be positioned to span the space between said one ledge and said anchoring means so as to trap the periphery of said aperture mask against said one ledge when the periphery of said aperture mask is placed in juxtaposition and in continuous engagement with said one ledge,

References Cited UNITED STATES PATENTS 2,690,518 9/1954 Fyler et a1. 313 2,824,989 2/ 1958 Christolferson 313-85 2,897,392 7/1959 Fiore 313-85 2,906,904 9/1959 Woughter et al. 313-85 2,961,560 11/1960 Fyler 313-64 3,005,921 10/ 1961 Godfrey 313-85 3,038,096 6/1962 Knochel et al. 313--85 ROBERT SEGAL, Primary Examiner.