CN1993797A

CN1993797A - Unified magnetic shielding of tensioned mask/frame assembly and internal magnetic shield

Info

Publication number: CN1993797A
Application number: CNA2004800431295A
Authority: CN
Inventors: P·芬克尔; R·R·穆特索
Original assignee: RCA Licensing Corp
Current assignee: Thomson Licensing SAS; RCA Licensing Corp
Priority date: 2004-05-27
Filing date: 2004-08-12
Publication date: 2007-07-04
Also published as: WO2005119726A1; EP1754239A1; EP1754239A4; JP2008500696A; MXPA06013702A

Abstract

The present invention provides a cathode ray tube (CRT) (1), comprising a tensioned mask frame (20) for supporting a tension mask (10) inside the CRT at a cantilevered edge thereof, a tension mask mounted on the tension mask frame at the cantilevered edge; and an internal magnetic shield (50) mounted on the tension mask frame. At least one of the tension mask (30) and the internal magnetic shield (50) have an extension (55, 56) extending along the tensioned mask frame (20) to a point proximate or contacting the other of the tension mask (30) and the internal magnetic shield (50) to provide magnetic coupling between the tension mask and the internal magnetic shield independent of the tensioned mask frame.

Description

The unified magnetic shielding cover and the inner magnetic shielding of tension mask/frame assembly

The cross reference of related application

The application require on May 27th, 2004 application, denomination of invention is the priority of the U.S. Provisional Patent Application No.60/574887 of " having the unified magnetic shielding cover of tension mask/frame assembly and the cathode ray tube of inner magnetic shielding ", its full content is incorporated by reference in the lump at this.

Technical field

The present invention relates to cathode ray tube (CRT), and be particularly related to a kind of radome device that is used for tension mask/frame assembly and inner magnetic shielding (IMS).

Background technology

Color cathode ray tube, or CRT comprise the electron gun that is used to produce and three-beam electron-beam is guided into fluorescent screen of ray tube.Phosphor screen is positioned at the inner surface of the fluorescence panel of ray tube, and is formed by the phosphor elements array of three kinds of different glow colors.Shadow mask can be shaping shadow mask or the tension mask that has strand or have the film that slit aperture has or do not have connecting rod, between electron gun and phosphor screen.Get on the phosphor screen by the aperture on the shadow mask from the electron beam that electron gun is launched, thereby make light-emitting phosphor that image is presented on the visible surface of fluorescence panel.

Tension mask comprises that one group reduces under externally the excitation tendency with large-amplitude vibration at the strand of straining on the shadow mask frame.This vibration will cause electron beam misregister total on the phosphor screen and will cause the bad anamorphose of CRT monitor.

Another source of electron beam misregister and electron beam motion is the remanent magnetism of CRT inside.In order to remove this remanent magnetism, carry out demagnetization and handle.One of the Control Parameter that is used for optimizing the magnetic property of cathode ray tube is that demagnetization recovers.The present cathode ray tube of good demagnetization recovery table is handled in IMS, shadow mask and the framing component of CRT inside after the equilibrium establishment magnetic field through demagnetization, when cathode ray tube is arranged in signal magnetic field externally, have low electron beam motion, and have good electron beam picture registration with phosphor elements on the phosphor screen.Along with using tension mask to comprise the introducing of the real Flat-Panel CRT that focuses on tension mask, make difficult more that the magnetic screen optimization become by demagnetization.

In the cathode ray tube degaussing process, the existence of IMS must realize the coupling of effective magnetic field by interfering framework and shadow mask.In the design of tension mask CRT, shadow mask is fixed on the rigid frame.In order to keep the tension force in the tension mask, framework must have high yield stress, and high yield stress is accompanied by poor magnetic usually, that is, and and high coercive force and low magnetic permeability.This makes the demagnetization of framework more difficult, causes poor magnetic flux coupling in degaussing process, and causes at the very high remnant field in CRT inside.These remnant fields cause CRT to have the purity of high electron beam misregister, difference and the picture quality of difference.

Expectation obtains a kind of improved shadow mask-frame assembly, makes tension mask demagnetization equably.

Summary of the invention

The invention provides a kind of cathode ray tube (CRT), comprising: be used for supporting at the cantilever edge place tensioned mask frame of the tension mask of CRT inside, tension mask is installed on the tensioned mask frame at the cantilever edge place; And inner magnetic shielding is installed on the tensioned mask frame.In tension mask and the inner magnetic shielding at least one has extension, and this extension extends to along tensioned mask frame on another the position that comes close to or in contact with in tension mask and the inner magnetic shielding with at tension mask be independent of between the inner magnetic shielding of tensioned mask frame magnetic coupling is provided.

Description of drawings

Present invention is described with reference to accompanying drawing below by example:

Fig. 1 is the sectional view of conventional cathode ray tube;

Fig. 2 is the front view that is used for the tension mask/frame assembly of Fig. 1 cathode ray tube, has shown the tension mask of local removal;

Fig. 3 is the perspective view of existing tension mask/frame assembly and inner magnetic screen closure assembly;

Fig. 4 is the side cross-sectional view of the tension mask/frame assembly and the inner magnetic screen closure assembly of the exemplary embodiments according to the present invention;

Fig. 5 is the side cross-sectional view of the tension mask/frame assembly and the inner magnetic screen closure assembly of another exemplary embodiments according to the present invention;

Fig. 6 is the tension mask/frame assembly of another exemplary embodiments according to the present invention and the perspective view of inner magnetic screen closure assembly;

Fig. 7 is the tension mask/frame assembly of another exemplary embodiments according to the present invention and the perspective view of inner magnetic screen closure assembly;

Fig. 8 is the side cross-sectional view of the tension mask/frame assembly and the inner magnetic screen closure assembly of another exemplary embodiments according to the present invention;

Fig. 9 is the side cross-sectional view of the tension mask/frame assembly and the inner magnetic screen closure assembly of another exemplary embodiments according to the present invention; And

Figure 10 is the side cross-sectional view of the tension mask/frame assembly and the inner magnetic screen closure assembly of another exemplary embodiments according to the present invention.

Embodiment

Fig. 1 represents to have the cathode ray tube 1 (CRT) of glass bulb 2, and glass bulb 2 comprises rectangular faceplate panel 3 and the tubular neck portions 4 that is connected by glass awl 5.Glass awl 5 has the internal conductive coating (not shown) that extends to panel 3 and neck 4 from anode button 6.Panel 3 comprises that one is essentially access panel 8 cylinder or rectangle and peripheral flange or sidewall 9, and is sealed on the glass awl 5 by frit 7.The inner surface of fluorescence panel 3 is provided with tricolour phosphor screen 12.This phosphor screen 12 is a kind of line phosphor screens of arranging photoluminescence line in ternary mode that have, the photoluminescence line of one group of color in the corresponding three kinds of colors of each bar of three photoluminescence lines of this group.Spaced relationship according to predetermined with phosphor screen 12 removably is installed with and selects look tension shadow mask assembly 10.The electron gun 13 that is schematically shown by dotted line among Fig. 1 is installed in the central authorities of neck 4, and to produce and the in-line electron beam of guiding three beams, promptly central beam and two lateral bundles or external beam make them pass tension shadow mask assembly 10 along convergence path and arrive phosphor screen 12.

Cathode ray tube 1 is designed to use together by a near external magnetic deflection yoke 14 that illustrates glass awl-tubular neck portions joint.When being subjected to encouraging, yoke 14 in three-beam electron-beam, makes scanning horizontally and vertically in the rectangular raster of electron beam on phosphor screen 12 with the action of a magnetic field.

As shown in Figure 2, tension shadow mask assembly 10 comprises a metal framework 20, and framework 20 has two

long limits

22 and 24 and two minor faces 26 and 28.Two

long limits

22,24 of framework are parallel to the central longitudinal axis X of cathode ray tube; Two

minor faces

26,28 are parallel to the central minor axis Y of cathode ray tube.Though for simple purpose, here with tension shadow mask assembly 10 simple be expressed as sheet, but it comprises a shadow mask 30 that cracks with many strip metals band (not shown), and many elongate slit (not shown) that are parallel to shadow mask 30 minor axis axis are arranged between these metal tapes.

Long limit

22,24 has the cantilever edge 25 of extending towards phosphor screen 12.

As shown in Figure 3, in the existing apparatus of tension shadow mask assembly 10 and inner magnetic shielding (IMS) 50, tension mask 30 is fixed on the cantilever edge 25 on

long limit

22,24 of tensioned mask frame.For example this fixing can adopt welding to carry out.IMS 50 is on the long limit that is fixed on framework 20 on the position of leaving tension mask 30.In the embodiment shown in Fig. 3, the

long limit

22,24 of framework 20 comprises L shaped bar or the angle that is formed by the two legs that is mutually the right angle, and wherein cantilever edge 25 is positioned at an end of one leg, and IMS 50 is fixed on other one leg.Therefore, existing radome device provides the magnetic flux coupling by tensioned mask frame 20.

In this device, IMS 50, tension mask 30 and framework 20 are all made by mild steel or iron-nickel alloy.If each parts all has the magnetic permeability of high no hysteresis effect and low coercivity, the magnetic screen and the demagnetization ability of tension mask 30, tensioned mask frame 20 and IMS 50 systems can both improve.But tensioned mask frame 20 must have high yield stress to be provided and plays the required hardness of suitable effect.This high yield stress is accompanied by poor magnetic usually, for example, and high coercivity and low magnetic permeability.Even the coercivity of tension mask 30 and IMS 50 is lower, the magnetic that expression is good, if the coercivity of tensioned mask frame 20 is higher, the magnetic of expression difference, the overall performance of cathode ray tube also can variation.Owing to have high magnetic resistance, tensioned mask frame 20 has increased the magnetic resistance of IMS/ frame/mask assembly.In addition, be difficult to remove at tension mask 30 and tensioned mask frame 20 residual remnant field at the interface after the demagnetization, and cause electron beam misregister.Traditional demagnetization is to utilize special anti-magnetized coil to place near IMS 50 to realize, and will make IMS 50 demagnetization fully.Yet traditional demagnetization has the effect of the remnant field in the tension mask 30 of the tensioned mask frame 20 of high coercivity and its back for removal little.Tensioned mask frame 20 causes magnetic field of the earth distortion and concentrates on the special point, and this makes that tension mask 30 and IMS 50 are magnetized when the ray tube demagnetization.In addition, owing to have very difficult removal of remnant field that the tensioned mask frame 20 of high coercivity is caused, and cause electron beam misregister.

As shown in Figure 4, in an exemplary embodiments of the present invention, tension mask 30 is fixed on the

long limit

22,24 of framework 20 at cantilever edge 25 places.IMS 50 has the

extension

55,56 that the surface corresponding to the

long limit

22,24 of tensioned mask frame 20 that is formed on IMS 50 ends is perpendicular to one another.When IMS 50 is fixed on the tensioned mask frame 20, prolong on Shen portion 55 extends to position near cantilever edge 25 along tensioned mask frame 20, be fixed on the tensioned mask frame 20 at tension mask 30 on this position.Extension 55 can contact tension mask 30, but this not necessarily.Randomly, the IMS 50 in the present embodiment can only be fixed on the tensioned mask frame at extension 56 places, with easy operating when assembling.Should be noted that extension 55 does not need to contact IMS 50 magnetic coupling is provided.Thereby tension mask 30 and IMS 50 can carry out magnetic coupling by little slit and minimal magnetic flux bleed-through.Randomly, the IMS 50 in the present embodiment can only be fixed on the tensioned mask frame at extension 56 places, with easy operating when assembling.

As shown in Figure 5, in a selectable exemplary embodiments of the present invention, one or more connecting elementss 60 are fixed on the tension mask 30 at cantilever edge 25 places of tensioned mask frame 20, and are fixed on the IMS 50 in the position away from cantilever edge 25.Connecting elements 60 can be formed by the material with high magnetic permeability, for example steel.Connecting elements 60 can be extremely thin with reduce with the wall of ray tube or ray tube in the contacted danger of other structure.Equally, the end of connecting elements 60 can be flat or appoint one or both ends all to be the crooked tension mask 30 that better contacts.Connecting elements 60 can contact tensioned mask frame 20, but this contact is optional.

As shown in Figure 6, in another alternate embodiments of the present invention, comprise that the flexible mesh screen 70 of ferromagnetic material extends between tension mask 30 and IMS 50.Mesh screen 70 can be as shown in Figure 6 extension below tension mask 30 and IMS 50.As shown in Figure 6, mesh screen IMS 70 can extend around the angle on the angled

long limit

22,24 of tensioned mask frame.Selectively, mesh screen 70 can extend around the angle on angled

long limit

22,24, allows extra gap.Mesh screen 70 can pass through fixing means, and for example welding is fixed on tension mask 30 and the IMS 50, and can be welded on the tensioned mask frame 20 with tension mask 30 and IMS 50.

As shown in Figure 7, in another alternate embodiments of the present invention, one or more lugs 80 are formed on the end of IMS 50, and they extend towards tension mask 30 when IMS 50 is installed on the tensioned mask frame 20 like this.Lug 80 can have different sizes and spacing to provide enough magnetic couplings between IMS 50 and tension mask 30.Lug 80 can extension below cantilever edge 25 is in tension mask 30, perhaps can be fixed on the tensioned mask frame 20 near cantilever edge 25 places.Begin to extend though lug 80 shows from IMS 50, lug selectively extends to form from tension mask 30 and towards IMS 50.

As shown in Figure 8, in another alternate embodiments of the present invention, coating 90 is applied on the tensioned mask frame 20 of the fixed area between tension mask 30 and the IMS 50.Coating comprises the material with high magnetic permeability, provides from the magnetic coupling of tension mask 30 to IMS 50.Coating 90 can be extended on the cantilever edge 25 of tensioned mask frame 20, and extremely away from the zone on the tensioned mask frame 20 of cantilever edge 25, when tension mask 30 and IMS 50 were fixed on the tensioned mask frame 20, coating 90 contacted with tension mask 30 and IMS 50 like this.Selectively, coating 90 can be extended near tension mask 30 and IMS 50, but does not contact with any or two in them.

As shown in Figure 9, in another selectable exemplary embodiments of the present invention, tension mask has the extension 35 that cantilever edge of crossing 25 is extended.These extensions 35 form as the part of tension mask 30, along tensioned mask frame 20 extend near or with IMS 50 contacted positions on, be fixed on the tensioned mask frame 20 at the local extension 35 that leaves cantilever edge 25.IMS 50 and extension 35 can adopt general fixing means to be fixed on the tensioned mask frame 20, for example can be spot welding.

As shown in figure 10, in another alternate embodiments, extension 100 is fixed on the

long limit

22,24 of framework 20, and the inner surface from IMS 50 beginnings along framework extends towards shadow mask 30.Compare with framework 20, extension 100 comprises the material with high magnetic permeability.Extension 100 can be by the separate part that is fixed with pressure, and for example presses to and cantilever edge 25 opposed edges.Extension 100 can insert from the inside of tensioned mask frame 20, with the shielding of reinforced frame 20.Should be noted that extension 100 can contact with shadow mask 30, but do not need direct contact, as long as extension 100 extends near on the place of shadow mask 30.

Previous exemplary has illustrated implements possibilities more of the present invention.Many other embodiment are possible in scope and spirit of the present invention.Therefore, the description of front should be thought illustrative and not restrictive, and scope of the present invention is limited by the additional claim and the equivalent of four corner thereof.

Claims

1, a kind of cathode ray tube (CRT) comprises:

Be used for supporting the tensioned mask frame of the tension mask of CRT inside at the cantilever edge place,

Tension mask is installed on the tensioned mask frame at the cantilever edge place; And

Inner magnetic shielding is installed on the tensioned mask frame; Wherein

In described tension mask and the described inner magnetic shielding at least one has extension, described extension extends to along described tensioned mask frame on another the position that comes close to or in contact with in described tension mask and the described inner magnetic shielding, with at described tension mask be independent of between the described inner magnetic shielding of described tensioned mask frame magnetic coupling is provided.

2, there is not direct contact in cathode ray tube as claimed in claim 1 between wherein said tension mask and the described inner magnetic shielding.

3, cathode ray tube as claimed in claim 1, wherein extension be on the tension mask with the equitant extension of inner magnetic shielding.

4, cathode ray tube as claimed in claim 1, wherein extension is to be fixed on the tension mask near cantilever edge and to be fixed on the inner magnetic shielding near the locational connecting elements that leaves cantilever edge on the tensioned mask frame.

5, cathode ray tube as claimed in claim 1, wherein extension is to comprise the flexible mesh screen that ferromagnetic material extends between tension mask and inner magnetic shielding.

6, cathode ray tube as claimed in claim 5, wherein flexible mesh screen are fixed on the tension mask near cantilever edge and are fixed on the inner magnetic shielding and leave on the position of cantilever edge near on the tensioned mask frame.

7, cathode ray tube as claimed in claim 1, wherein said extension are formed at least one lug at shadow mask edge, extend on the position that comes close to or in contact with inner magnetic shielding along described tensioned mask frame.

8, cathode ray tube as claimed in claim 7, wherein at least one lug is fixed on tensioned mask frame and comes close to or in contact with on the position of inner magnetic shielding.

9, cathode ray tube as claimed in claim 8, wherein lug and inner magnetic shielding are fixed on the tensioned mask frame by general fixing means.

10, cathode ray tube as claimed in claim 1, wherein said extension are at least one lugs that is formed on the inner magnetic screen shroud rim, extend on the position that comes close to or in contact with tension mask along described tensioned mask frame.

11, cathode ray tube as claimed in claim 10, wherein lug is fixed on tensioned mask frame and comes close to or in contact with on the position of tension mask.

12, cathode ray tube as claimed in claim 1, wherein said extension is the coating with high-permeability material, is applied on the described tensioned mask frame between described tension mask and the described inner magnetic shielding.