Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
  • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
  • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
  • H01J29/06—Screens for shielding; Masks interposed in the electron stream
  • H01J29/07—Shadow masks for colour television tubes
  • H01J29/073—Mounting arrangements associated with shadow masks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2229/00—Details of cathode ray tubes or electron beam tubes
  • H01J2229/07—Shadow masks
  • H01J2229/0705—Mounting arrangement of assembly to vessel

Definitions

• the present invention relates to a color cathode ray tube comprising a color selection mask held in place by a rigid frame, and more precisely the means for suspending the frame / mask assembly inside the tube.
• the invention finds its application in any type of tube comprising a mask for selecting colors, and is equally well suited to the tube whose mask is produced by stamping as to the tube whose mask is stretched over the edges of the rigid frame on which he is united.
• a conventional color cathode ray tube is composed of a vacuum glass envelope.
• the tube has, inside the envelope, a color selection mask located at a precise distance from the glass front face of the tube, front face on which are deposited arrays of red, green and blue phosphors to form a screen.
• An electron gun placed inside the tube, in its rear part, generates three electron beams in the direction of the front face.
• An electromagnetic deflection device generally placed outside the tube and close to the electron gun, has the function of deflecting the electron beams in order to make them scan the surface of the panel on which the phosphor networks are arranged. Under the influence of three electron beams each corresponding to a specific primary color, the phosphor networks allow the reproduction of color images on the screen, the mask allowing each determined beam to illuminate only the luminophore of the color. corresponding.
• the color selection mask must be placed and maintained during the operation of the tube in a precise position inside the tube.
• the mask holding functions are performed by means of a generally very rigid rectangular metal frame on which the mask is conventionally welded.
• the frame / mask assembly is mounted in the front face of the tube by means of suspension means welded to the frame and cooperating with pins inserted in the glass constituting the front face of the tube.
• the color selection mask is produced from a very thin metal sheet and comprises a surface known as an effective surface, pierced with openings, said openings being produced by chemical etching and generally arranged in vertical columns; the effective surface is surrounded by a non-perforated peripheral border.
• the mask is generally attached to the frame by spot welding at the peripheral edge.
• the frame / mask assembly is suspended in the front face of the tube by means of elastic support means secured to the frame and cooperating with the pins inserted in the glass wall of the front face. .
• the support means must have sufficient elasticity to allow the frame / mask assembly to be disassembled several times from the front face during the various phases of the phosphor network manufacturing process.
• the support means are generally arranged either in the middle of the sides of the frame or at the corners of said frame. In all cases, given the large number of operations for inserting and removing the frame / mask assembly relative to the front face, it may result that the final position of said assembly, and therefore of the mask relative to the 'phosphor screen, or slightly offset from said screen.
• This offset can also be generated after the manufacture of the tube by a mechanical impact on said tube. In all cases this offset causes discoloration of the images by the fact that the mask is not at the right distance from the screen.
• the invention provides a support structure for the frame / mask assembly which is not very sensitive to shock and vibrations and which makes it possible to best guarantee the distance required between the mask and the phosphor screen.
• the cathode ray tube comprises: - a mask for selecting colors - a frame intended to hold the mask in place inside the tube,
• - support elements of the frame inside the tube at least one of the support elements comprising a first arm, welded at one end to the frame, and a second arm, forming a spring, of which a first end has an opening intended to cooperate with a pin integral with the glass envelope of the cathode ray tube and the second end of which is welded to the second end of the first arm, the two arms extending so that their first end is arranged substantially in the one facing the other, said support elements being characterized in that they further comprise a tongue, integral with the frame, and extending in the direction of the end of the second arm so as to be able to cross this end through a slot made in said end.
• FIG. 1 is a side sectional view of a cathode ray tube incorporating the present invention.
• FIG. 2 is a partial top view of the front face and of the frame / mask assembly of the tube of Figure 1 - Figure 3 is a sectional view, at a corner, of the front face showing a support for a frame / mask assembly according to the state of the art
• FIG. 4 is a detailed view of the support means of Figure 3
• FIG. 6 shows a sectional view of a second embodiment of the invention.
• FIG. 1 describes a cathode ray tube of the color type 8 comprising a glass envelope 10, composed of a front face 12, a flared rear part in the form of a funnel 16 terminated by a cylindrical neck 14.
• the front face is composed of a substantially flat part 18 serving as a display screen surrounded by a peripheral skirt 20, the end edge of which is sealed to the rear part 16.
• the front face 12 comprises two orthogonal axes, l major axis XX, parallel to its largest dimension, generally the horizontal direction, and a minor axis YY, parallel to its smallest dimension, generally the vertical direction. These two axes are perpendicular to the longitudinal axis ZZ of the tube which passes through the center of the cylindrical neck 14 and the center of the front face 12.
• a screen 22 made of a mosaic of phosphors of the three fundamental colors red, green and blue is deposited on the internal surface 18 of the front face.
• a color selection electrode 24, also called a shadow mask, has an effective surface, facing the front face, pierced with a multitude of orifices; this electrode is held in place in the tube, at a precise distance from the screen 22, by means of the invention, adapted to allow the mask to be applied and deposited during the various stages of manufacture of the tube.
• An electron gun 26 is placed in the neck of the tube so as to generate three electron beams converging on the screen 22 through the orifices of the mask 24.
• the first flange 36 extending in the direction of the screen and a second flange 38 extending in a direction substantially parallel to the 'screen, towards the longitudinal axis ZZ.
• the corners 42 of the frame are truncated with a surface substantially perpendicular to the diagonal of the frame.
• the mask 24 includes an effective part 25, comprising a multitude of openings, bordered by a non-perforated part 27 and a skirt 29, folded with respect to the part 27 to extend opposite the screen 22; the mask is then secured to the frame by welding of the skirt 29 on the flange 36. Alternatively, the mask can be stretched and kept in tension by welding on two parallel edges of the flange 36.
• the frame / mask assembly is held inside the tube by support means 34 integral with the frame and cooperating with pins 44 inserted in the skirt 20 of the front face.
• These support means can be arranged either near the middle of the sides of the frame, or as illustrated in FIG. 2, at the corners of the frame.
• the support means 34 comprise two arms 46 and 48 made from two elongated metal plates. The plate 48 is welded at one of its ends 53 to the flange 36 and at the opposite end 54 to one of the ends 51 of the arm 46.
• This arm 46 forms a spring and has a second end 50, substantially arranged facing the end 53 of the arm 48; the end 50 includes an opening 55 to cooperate with the pin 44, said pin of substantially frustoconical shape passing through the opening 55 to ensure the suspension and the maintenance of the frame / mask assembly.
• the ends 50 and 51 of the spring arm 46 are connected by an intermediate part 52 folded relative to the planes of these ends so as to create a clearance zone allowing, by spring effect, to release the end 50 of the pin 44 by pushing on said end .
• the two arms 46 and 48 are generally made of the same material and are distinguished from one another by their thickness. The spring effect requested on the arm 46 means that it is generally of smaller thickness than the arm 48.
• the support means 34 also include a metal tongue 60 secured to the frame and extending towards the end 50 of the spring arm 46, which it crosses through a slot 61 made in this end.
• the tongue 60 and the arm 48 welded to the frame, form a unitary part; the tongue 60 is obtained from the same metal plate forming the arm 48, by cutting and folding so as to extend in a direction substantially orthogonal to the part 53 welded to the surface of the frame.
• the slot 61 is preferably arranged so as to extend in its greatest length 62 in a direction substantially perpendicular to the diagonal of the frame.
• the length 62 of the slot is identical, with the mechanical clearance, to the dimension of the tongue 60 in the same direction in order to block any parasitic movement of the end of the spring arm 46 and to avoid any rotation of this end around the frustoconical pin 44.
• FIG. 6 illustrates a second embodiment of the invention in which the tongue 60 ′ is dissociated from the support arms and is directly welded to the frame.
• the advantage of this structure is that you can use a same support arm system 46, 48 without blocking device for all the families of tubes manufactured and adding the blocking device in the form of the additional tongue 60 ′ only for the types of tubes having a sensitivity to shocks generating registry losses.
• FIG. 6 illustrates a second embodiment of the invention in which the tongue 60 ′ is dissociated from the support arms and is directly welded to the frame. The advantage of this structure is that you can use a same support arm system 46, 48 without blocking device for all the families of tubes manufactured and adding the blocking device in the form of the additional tongue 60 ′ only for the types of tubes having a sensitivity to shocks generating registry losses.
• FIG. 7 illustrates a third embodiment of the invention for which the opening in the end of the arm 46 is in the form of a notch 61 ′, the greatest length of which 62 corresponds, to the mechanical clearance present, to the length tongue 60 or 60 'in the same direction.
• the invention is not limited to the support means of the frame / mask assembly arranged at the corners of the frame but is likewise usable for support means arranged on the sides of the frame, generally near the middle of said sides.
• tubes incorporating both support means arranged in the corners and on the sides of the frame for example in very large tubes, which are by construction very sensitive to shocks due to the significant weight of the frame / mask assembly.
• the invention can be applied in tubes for which the frame is an integral part of the mask, said frame then being produced by folding the periphery of the mask.

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• Electrodes For Cathode-Ray Tubes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=32448915

Family Applications (1)

Country Status (7)

Family Cites Families (6)

• 2002
  • 2002-11-29 IT IT002539A patent/ITMI20022539A1/it unknown
• 2003
  • 2003-10-31 AU AU2003292301A patent/AU2003292301A1/en not_active Abandoned
  • 2003-10-31 CN CNB2003801037107A patent/CN1333425C/zh not_active Expired - Fee Related
  • 2003-10-31 EP EP03767867A patent/EP1565927A2/de not_active Withdrawn
  • 2003-10-31 JP JP2004556395A patent/JP2006508511A/ja active Pending
  • 2003-10-31 WO PCT/FR2003/003251 patent/WO2004051693A2/fr not_active Ceased
  • 2003-10-31 KR KR1020057009519A patent/KR20050086870A/ko not_active Withdrawn

Non-Patent Citations (1)

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