EP0858094A1 - Color picture tube with a maskframe assembly - Google Patents

Abstract

The colour television cathode ray tube has a mask Ä2Ü with a pattern of slots that is secured within a frame Ä1Ü. The mechanical stability of the mask -frame combination is enhanced by a series of spot welding points.ÄSP3,SP8Ü around the periphery. The mask profile is also formed with sectional features that stiffen the structure. The edge of the mask at the welding points is formed with a comb shaped profile.

Description

The invention relates to a color picture tube with a mask-frame combination according to the preamble of the claim 1.

With color picture tubes, three color separation pictures are overlaid pixel by pixel in which the to a pixel associated color dots can be arranged side by side. At the point structure from the Eye no longer perceived and an additive occurs Color mixing. The electron beams of the three Beam generation systems of color picture tubes or color monitors fall on the arranged on the fluorescent screen Fluorescent strips or dots. So only that Electron beam from one of the three electron beam generation systems for the three primary colors on the Fluorescent strips or dots of the corresponding color lands, shadow masks are used, which "shade" the other two electron beams. Around 80% of the beam generation systems end up in the process coming electrons on the shadow mask (shadow mask). This leads to heating and thus to an expansion of the Hole mask, which makes holes in their position opposite the Move fluorescent strips or fluorescent dots can.

The shadow mask or mask consists of thin, low carbon iron sheet or iron alloys. nowadays the masks are often made of iron-nickel alloys manufactured at low temperatures compared to iron have very little thermal expansion caused by Magnetostriction. There are about 400,000 holes in the mask etched, the approximately 600 triple stripes or the approximately 400,000 color point triples arranged in groups of three Fluorescent strips or fluorescent dots, each with a red, green and blue luminous stripes or dots are.

A certain mechanical stability around the thin shadow mask and to give manageability, the curved shadow mask is in or welded onto the mask frame. This is with modern Color picture tubes also made of thin sheet metal. The shadow mask with Frame and suspension must be at least so stable that the Picture tube a maximum permitted acceleration of 35g he wears. Because iron-nickel alloys are many times more expensive than iron, the mask frame (or frame) is made Iron is made, while the mask is made of an iron-nickel alloy consists.

When pulling such masks out of sheet metal, a mask shirt becomes formed and the mask surface bulged. The mask shirt will with a variety of weld spots with the frame connected. The connection between mask and Frame made of materials with different Thermal expansion coefficients are manufactured. At Warming the mask-frame combinations are deformations possible of the mask, which is the location of the holes in the mask relative to the spatial location of the assigned Change fluorescent strips or fluorescent dots. Especially because of the different Thermal expansion behavior of the mask and frame thermal manufacturing processes and when operating a Color picture tube or a color monitor is only a loose one Pairing required. On the other hand, there is high rigidity desired for the connection between mask and frame, so the mask does not deform and bend due to impact No sound waves from the loudspeaker of a television set Vibrations is excited.

One tries through these contradictory demands Stiffening beads in the mask, decoupling slots or Cutouts in the mask frame and the placement of the To meet welding spots at the same time.

A solution is proposed in EP-A1 063 322, which refers to iron mask with iron frame, the mask is welded outside the frame. It can be on one previously necessary manufacturing step (temperature treatment (Stabilization) in a continuous furnace). The location of the welding spots on the longer and shorter sides of the frame indicated by inequalities, the only certain areas on each page additionally to the cornerstones for the attachment of welding spots allow for the treatment of temperature treatments (e.g. Blackness stabilization, frits) occurring or remaining tensions in the material due to functional still allowable deformations within the remain elastic range. These weld spots must within a certain height range of the mask edge which, like the other range information from the Length of the mask diagonal is dependent. For decoupling There are also notches, recesses or sags provided which is located at the corners of the mask Welds on both sides of mechanical stresses relieve. One above the same serves the same purpose Edge of mask attached all around bead.

Another solution for masks made of iron-nickel alloys with iron frame, with the mask outside the frame is welded on, is proposed in EP A2 0518 249. A total of 12 are used to connect the frame and mask Spot welds used to make the mask shirt on the outside weld the frame. The welding spots are there each at the corners and roughly in the middle of each side. In addition, there are welding spots on the longer sides between the middle welding point and the Corner weld spot in an area near the middle Spot weld attached. Also, the weld spots placed as close as possible to the free edge of the mask shirt and the cutouts each take up almost the entire area between the welding points.

The object of the invention is for mask-frame combinations with masks made of iron-nickel alloys and frames made of iron, where the mask shirt is on the inside of the frame permanent deformation of the mask is caused by welding Avoid weakening the stiffness in order to avoid To be able to elastically compensate for differences in length, while maintaining stability to mechanical To be able to withstand stress.

This object is achieved by the features of patent claim 1 solved.

This allows the mask to start before the black stabilization process be welded into the frame and thus for additional Handling when blackening the mask and frame separately to be dispensed with. Likewise, the additional Heat treatment of the mask-frame combination in the associated glass pan in a continuous furnace (stabilization) to be dispensed with.

Differences in the change in length of the frame and mask to be able to compensate elastically in the event of temperature increases, are on both sides of the weld spots on the shorter sides notches or decoupling slots are attached to the mask. These notches allow the contours on the Sides of these welds after the common Black stabilization of the mask-frame combination in the Blackening furnace has no permanent changes in contour, especially if, in addition, the size ratios according to subclaims 2 and 7 are taken into account. The deeper the notches, the greater the elasticity effect. At the same time, as the depth of the notch increases the stability of the masks is reduced. If the claim 1 specified depth of notches not exceeded, see above Mask stability does not deteriorate either. With the depth of the notches according to the invention is therefore a the highest possible stability of the mask at the same time achieved the greatest possible elasticity of the mask.

It is particularly advantageous to have high stability with great To combine elasticity of the mask when one is too the notches further away from the welding points preferably provides decoupling slots that become smaller.

In addition, with increasing width and number of Notches or decoupling slots the elasticity of the Raise mask. At the same time, with increasing width the remaining mask shirt at the location of the Spot welds and between the notches or Decoupling slots increase the stability of the mask. For The solution to the problem depends on a suitable combination of these influencing factors.

The stability of the connection between the mask and the frame can be achieved with a minimum number of welding spots can be achieved, if the weld spots in addition to the corners and each one in the middle of the shorter side near the Be attached in the middle of the longer sides.

Fig. 1

eine Draufsicht auf eine Masken-Rahmen-Kombination mit Bezeichnung der Stellen, an denen vorzugsweise Schweißpunkte angebracht werden;

Fig. 2

einen Längsschnitt durch die in Fig. 1 gezeigte Masken-Rahmen-Kombination, entlang einer Linie vom Schweißunkt SP8 zum Schweißpunkt SP3;

Fig. 3

eine Draufsicht auf die Schweißpunkte SP3 und SP8 (Einzelheit A aus Fig. 1).

An embodiment of the invention is explained in more detail with reference to the drawing. Show it:

Fig. 1

a plan view of a mask-frame combination with a description of the locations where welding spots are preferably attached;

Fig. 2

a longitudinal section through the mask-frame combination shown in Figure 1, along a line from the welding point SP8 to the welding point SP3;

Fig. 3

a plan view of the welding points SP3 and SP8 (detail A from Fig. 1).

There is a mask-frame combination in the figures shown, which consists of a mask frame 1 and a mask 2nd consists. The mask that has holes or mask slits 3 is provided to only some of the electrons for the Fluorescent strips or fluorescent dots of the primary colors to let through on the inside of the front screen glass preferably made of an iron-nickel alloy with 36% nickel (FeNi36, Invar) with a small coefficient of thermal expansion produced. The coefficient of expansion of this Iron-nickel alloy is up to about 60 ° C less than one tenths below that of iron. Depending on the exact Alloy composition of this iron-nickel alloy lies the Curie point is usually between 200 and 300 ° C. Above of the Curie point is the expansion of an iron-nickel alloy essentially the same as that of iron. At further uniform heating of the mask and frame there are only further differences in length change due to a differently rapid temperature increase due to the different mass of frame and mask like even before reaching the Curie point. At the Cooling process also arise Differences in elongation caused by the different cooling behavior and the different coefficients of thermal expansion of Mask and frame.

The mask-frame combination is attached to the side Thermal bimetal springs attached to the picture tube pan ("buttoned in"). One of the springs is also with one Centering disc provided.

To increase the mechanical stability and the The thin slit or shadow mask is easy to handle Welded mask frame. The masks can be used both over the Frame put up and welded outside (in this Embodiment inside). The weld spots between the mask and frame then connect the mask shirt and the inner surface of the frame. The total of ten welding spots SP1 to SP10 sit at the with an arrowhead in Fig. 1st marked positions. Accordingly, there are four Spot welds (SP2, SP4, SP7, SP9) in the corners of the Combination arranged. Two more welding spots SP5, SP6 and SP10, SP1 sit on each of the long sides and are arranged near the middle. That way you can the mask shirt areas on the long sides between the middle welding points and the corner welding points low manufacturing effort, i.e. without additional Resiliently deform recesses in the mask shirt without it permanent deformation occurs. There is one welding spot each on the shorter sides, preferably in the middle arranged.

To increase the stiffness of the mask, it is above the mask shirt with a circumferential stiffening bead 5 Mistake.

The mask shirt 7 (in Fig. 2 is the height compared to Width exaggerated) is around the middle Spot welds on the shorter sides with notches and Provide decoupling slots so that the Mask shirt areas around the weld spots relatively free can move. For the highest possible stability with to combine the highest possible elasticity Notches 10 and decoupling slots 11 as in FIG. 3 shown, executed. Both sides of the Welding points SP3 and SP8 notches are provided and on the side of the notches facing away from the weld 10 additional decoupling slots at some distance appropriate. Both the notches 10 and the Decoupling slots 11 preferably have one arched shape. Likewise, all forms be used, which increases with depth, i.e. increasing distance from the outer edge of the mask, in their Taper width.

Particularly important for a particularly good fulfillment the stability and elasticity requirement is the depth (H2-H3) of the notches 10. It has been found that a relationship between the height of the mask shirt H2 and the remaining height H3 of the mask shirt at the location of the maximum depth of the notches 10 of 3: 1 the conflicting requirements particularly well met.

Further improvements can be achieved if the width ratios of the notches 10 also adhere to certain size ratios. For this purpose, the width B of the remaining mask shirt between the notches 10 adjacent to the welding points SP3 and SP8 and the width A of the notches 10 should have the following ratio: A / B = 2/3.

In addition, for a particularly good result, the average distance D of the notches 10 with a welding point position symmetrical to D to the greatest depth (H2-H3) of the notches 10 should have the following ratio: D / (H2-H3) = 23/17.

For a further improvement in the elasticity without additional weakening of the stability, additional decoupling slots 11 can be provided symmetrically to the position of the welding points SP3 and SP8, the average distance D of the notches 10 from the average distance E of the decoupling slots 11 having the following relationship: D / E = 23/50.

For an optimal result, the following ratio for the greatest depth (H2-H1) of the decoupling slots 11 to the greatest depth (H2-H3) of the notches 10 should be maintained: (H2-H1) / (H2-H3) = 11/17.

The following also applies to the ratio of the width A of the notches 10 to the width C of the decoupling slots 11: A / C = 9/4.

Claims (7)

Color picture tube with a mask-frame combination consisting of a rectangular frame (1) made of a first material and a mask (2) made of a second material, the mask being connected to the frame by a plurality of welding spots, characterized in that that the shorter sides each have a welding point (SP3, SP8), preferably approximately in the middle of the shorter sides; and Notches (10) are provided on both sides of the welding points (SP3, SP8) of the shorter sides, with their greatest depth (H2-H3) for the distance (H3) from the upper edge (13) of the mask shirt (7) to the height ( H2) of the mask shirt (7) approximately the following applies: H3 / H2 = 1/3, in which: H3 corresponds to the distance between the greatest depth of the notches (10) and the upper edge (13) of the mask shirt (7); and H2 corresponds to the height of the mask shirt (7). Color picture tube according to Claim 1, characterized in that the notches (10) have a width (A) which corresponds to the remaining width (B) of the mask shirt (7) around the welding points (SP3, SP8) of the shorter sides between the notches (10) is in the following ratio: A / B = 2/3, in which: A corresponds to the width of the notches; and B corresponds to the width of the welding web around the corresponding welding points between the notches (10). Color picture tube according to one of claims 1 or 2, characterized in that the average distance (D) of the notches (10) greatest to the depth (H2-H3) of the notches (10) has the following ratio: D / (H2-H3) = 23/17, in which: D corresponds to the average distance between the notches (10) on both sides of the welding points; and (H2 - H3) corresponds to the depth of the notches (10). Color picture tube according to one of Claims 1 to 3, characterized in that each of the notches (10) on the side facing away from the welding points (SP3, SP8) has additional decoupling slots (11) at a certain distance, the mean distance E of which has the following ratio to the mean Distance D of the notches (10) is: D / E = 23/50, in which: D corresponds to the average distance between the notches (10); and E corresponds to the average distance between the decoupling slots (11). Color picture tube according to claim 4, characterized in that the greatest depth (H2-H1) of the decoupling slots (11) to the greatest depth (H2-H3) of the notches (10) has the following ratio: (H2-H1) / (H2-H3) = 11/17; in which: (H2-H1) corresponds to the greatest depth of the decoupling slots (11); and (H2-H3) corresponds to the greatest depth of the notches (10). Color picture tube according to one of claims 4 or 5, characterized in that the width (A) of the notches (10) to the width (C) of the decoupling slots (11) has the following ratio: A / C = 9/4, in which: A corresponds to the width of the notches (10); and C corresponds to the width of the decoupling slots (11). Color picture tube according to one of claims 1 to 6, characterized in that the mask shirt (7) lies against the inside of the frame (1) and is welded on; and the mask-frame combination welding spots (SP2, SP4, SP7, SP9) in each of the four corners, at least one welding spot (SP1, SP5, SP6, SP10) on each of the longer sides and a welding spot (SP3, SP8) on each of the has shorter sides.

Images