KR0153463B1 - Material and process for the manufacture of tension masks for cathode ray tubes - Google Patents

Abstract

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Description

Tensile thin film shadow mask for CRT and its manufacturing method

1 is a perspective view of a colored CRT with a flat faceplate and a flattened faceplate, with a partially cut cross section showing the position and relationship of the stretched thin film shadow mask and face plate relative to the other major tube components;

2 is a plan view of a thin film shadow mask;

3 is a plan view of a flat glass faceplate showing a thin film shadow mask support structure secured to a flat screen area,

4 is a perspective view of the funnel sighting and fritting fixture with the funnel and faceplate to be attached as shown mounted to the fixture,

5 is a front view and a detailed partial view showing the attachment of the funnel to the face plate.

FIELD OF THE INVENTION The present invention relates generally to tensile thin film color CRTs, in particular to providing a desired combination of mechanical and magnetic properties necessary for the effective operation of the tensile thin film shadow mask formed from the improved alloy and the tensile thin film shadow mask. It relates to a process for producing such a CRT, including iron alloy heat treatment. Also described is a front assembly containing such a mask.

CRTs having flat faceplates and thinly tensioned shadow masks are known to provide many advantages over conventional CRTs with curved faceplates and curved shadow masks. The main advantage of a flat faceplate CRT with a tensioned mask is the ability to adjust electron beam power, which can provide greater image brightness. The power adjustment capability of CRTs with existing curved masks is limited to the thickness of the mask (5-7 mils), which in fact is not installed under tension. As a result, the mask is expanded or dome in the image area of high luminance, where the intensity of electron beam impact and the intensity of heating are greatest. Color impurity occurs when the mask is expanded to the faceplate and the beam passing aperture in the mask deviates from the registration with the associated fluorescent point or fluorescent line on the faceplate.

When heated, the stretched thin film mask behaves in a very different way than the curved, untensioned mask. For example, if the entire mask is heated unevenly, the mask is expanded and the tensile force is alleviated. This mask remains flat and no twisting or doping occurs until the mask is expanded to the point where the tensile force is completely lost. Just before all the tensile force is lost, wrinkles may occur at the corners. When the small area of the stretched thin film mask is heated differently, the heated area expands and the unheated area correspondingly shrinks, resulting in only a small displacement in the mask plane. However, the mask remains flat, properly spaced from the faceplate and consequently no color impurity is noticeable.

Such a mask must be kept in tension to keep the mask flat during the operation of the CRT. The required tensile force will depend on how much the mask material expands with heating during the operation of the round tube. Materials with very low coefficients of thermal expansion require only low tensile forces. However, in general, the greater the tension, the greater the heat generated and the greater the electron beam current to be adjusted, so the tension should be as high as possible. However, mask tension is limited because too much tension can rupture the mask.

The thin film mask can be tensioned according to known methods. A convenient way is to thermally expand the mask by heated platens applied to both sides of the thin film mask. The inflated mask is then clamped into the fixture upon cooling and held under tension. Such masks may also be inflated by exposure to infrared radiation, by electrical resistive heating, or by stretching through the application of mechanical force to the edges.

In addition to having a composition as described herein, after heat treatment and slow cooling in accordance with the present invention, thin films constructed from alloys are the only combination of dropping mechanical, thermal and magnetic properties for use as tensioned thin film shadowmasks. Will have.

The alloy in cast or treated form must have a ductility that allows it to be hot or cold rolled into a thin film having a thickness of less than 2mis, preferably as thin as 1 mil or as thin as 0.5 mil. When rolled, a 1 mil thick film will typically have a minimum area reduction of 0.8% and an extension of 1.0%. In order to withstand the forces susceptible to tensile action, the mask material must have a yield strength of approximately 80 ksi or more and preferably 100 ksi (0.2% offset) or more. The mask material must also be able to withstand a tensile load of approximately 25 N / cm, preferably at least 65 N / cm. The mask material should also have a coefficient of thermal expansion that is actually not significantly smaller than the coefficient of thermal expansion of the glass of the faceplate.

In addition to the mechanical properties described, the mask material must have a specific combination of magnetic properties. In this regard, it is important for the mask material to have as high permeability as possible while maintaining the required mechanical properties. This permeability should be approximately 6,000, preferably at least approximately 10,000, more preferably up to 60,000. The maximum coercivity is preferably less than approximately 1.0 Hersted, preferably less than 0.5 Hersted.

It is known to heat the shadow mask prior to its formation in the form of a dome in the manufacture of standard color CRTs of curved masks and curved screens. Existing (unsaddled) shadow masks are typically delivered to CRT manufacturers in a process-cured state by a plurality of rolling operations performed on steel to reduce to a specific thickness of approximately 6 mils. In order to stamp the mask in the form of a dome, the mask must typically be softened using annealing heat treatment at a temperature on the order of 700 to 800 ° C. Furthermore, annealing enhances the magnetic coercivity of the mask, which is a desired property from the standpoint of magnetic shielding of the electron beam. After subsequent proper work hardening of the mask, which can be derived from stamping and stamping operations, it is known in the art to re-anneal the mask in a bent form to further enhance the magnetic shielding properties.

Thin films for use as tensioned masks are also supplied in a hardened state, much harder than standard masks, to provide the very high tensile strength required to maintain the required high tensile levels, for example 30,000 psi or more. Prior art annealing treatments with relatively high annealing temperatures are absolutely weak when applied to flat tension masks because they make materials unsuitable for use as tensile masks by excessively weakening or reducing the tensile strength of the mask resulting from the treatment. Unacceptable

U.S. Patent No. 4,210,843 to Abidani presents an improved method of making a conventional color CRT shadow mask, that is, the curved shadow mask has a thickness of approximately 6 mils and is used with a correspondingly curved faceplate. It is designed to. The method includes providing a plurality of shadow mask blanks, each consisting of a gap-free steel with a pattern of photo etched openings, wherein the blank is precision cold rolled to a thickness of 6 to 8 mils and fully cured. Cut from a thin film of steel. Lamination of the blank is subject to a limited annealing process performed in a relatively short period sufficient to achieve recrystallization of the material without causing significant particle growth at relatively low maximum temperatures. Each blank is clamped and drawn to form a concave shadow mask without imposing roller leveling motion and vibration and avoids unwanted work-hardening, splitting, dents, or marking of the blanks typically associated with such motion. . The shadow mask, a finished product due to the use of a gap-free steel material, has an improved sharpness opening pattern as a result of more uniform stretching of the mask blank. The annealing action has little effect on the magnetic properties of this type of steel, and after formation the coercivity of the material is greater than 2.0 erstets.

In the previous invention, there were no thin film mask materials available that had a good combination of mechanical and magnetic properties described in the present invention. The material used for thin-film shadowmask applications stretched in flat faced cathode ray tubes is aluminum-killed, AISI 1005 cold rolled cap steel, commonly referred to as AK-steel. AK-steel has a composition of 0.04% silicon, 0.16 manganese, 0.028% carbon, 0.020% phosphorus, 0.018% sulfur, 0.04% aluminum and the rest iron and incidental impurities.

(Through the specification and claims, all percentages are to be regarded as weight-percent, not otherwise indicated.)

Invariant steels having a nominal composition of 36% nickel and the remaining iron have been proposed as possible materials for tensioned thin film shadow masks. However, Invar has a coefficient of thermal expansion far lower than that of glass used in CRT faceplates and is generally unacceptable.

AK-steel can be configured with a thinly acceptable shadow mask, but lacks some important properties. For example, the yield strength of AK-steel thin films with a thickness of 1 mil is in the range of 75 to 80 ksi. This makes it only acceptable from a strength point of view. In particular, AK-steel has a permeability of less than 5,000, for example, at 1 mil thin films. Because the material's ability to carry magnetic flux decreases with decreasing cross-section, CRTs with masks made of AKsteel thinner than 1 mil may require internal and external magnetic shielding. With only internal shielding, the change in the beam landing position at the time of reversal of the axial field component, i.e., the beam landing error registration due to the earth's magnetic field, is typically 1.7 mils, which is generally much higher than the maximum allowed tolerance of 1 mil. Big.

In addition, AKsteel is a metallurgical dirty material that has potentials and bonds and inclusions that interfere with the optical insulation etching of the openings and thin film rolling processes in thin films, resulting in low yields and high scrap rates.

Another important disadvantage of the AKsteel tensile thin film shadow mask is that the permeability decreases and the coercivity increases as the applied tensile force increases. Once the image performance is transformed, when the far field of the AK-steel thin-film shadow mask is increased to allow for increased beam current, thus allowing greater image brightness, the ability to shield the electron beam from the earth's magnetic field is degraded, resulting in beam errors. Increase registration

Finally, AKsteel is rusted and requires careful storage, and requires the application of rust inhibitors. If rusted, the molten mask must be removed from the product behavior of the fluctuations without changing the thickness of the mask material or the size and shape of the openings.

In general, the present invention aims to provide an improved shadow mask material for use in a color CRT with a tensioned thin film shadow mask.

Thus, the present invention provides a thin film shadow mask for use in a tensioned thin film color CRT, wherein the thin film mask is between 30% and 85 weight-percent nickel, between 0 and 5 weight-percent molybdenum, and It consists of an alloy containing one or more of vanadium, titanium, hafnium and niobium in weight-percentages between two.

Another general aspect of the present invention is to provide an improved method for producing a CRT tube containing a tensile thin film mask having improved mechanical and magnetic properties.

Thus, the present invention provides a method for producing a tensioned mask color CRT having a mold and a screen on an inner surface and a face plate having a support structure for the mask on the opposite side of the screen. The method comprises the steps of providing an apertured thin film shadow mask composed of a nickel-iron alloy, adhering the mask to the support structure under tension in conformity with the fluorescent screen; Placing the mask under thermal cycle to partially anneal the mask to a state in which the mask has good mechanical and magnetic properties.

Other features and advantages of the invention will be best understood by reference to the following description of the preferred embodiments of the invention in connection with the accompanying drawings (not standardized). In addition, in some drawings, like numerals refer to like elements.

In order to facilitate understanding of the manufacturing relationship of colored CRT tubes with tensioned thin film shadow masks and the materials and treatments according to the invention, a brief description of the main components and tubes of this type will be given below.

1 shows a color CRT 20 having a stretched thin film shadow mask. The faceplate assembly 22 basically comprises a flat faceplate and a tensioned flat thin film shadow mask mounted adjacent thereto. The faceplate 24 shown in the rectangle is shown as a fluorescent screen positioned in the center shown as having a pattern of fluorescence on the inner surface 26. The aluminum thin film 30 is shown covering the pattern of fluorescence. The funnel 34 appears to be attached to the faceplate assembly 22 at the interface 35, and the funnel sealing surface 36 of the faceplate 24 appears to be around the screen 28. A shadow mask support structure 48, such as a frame, is shown to be located on the opposite side of the screen between the funnel sealing surface 36 and the screen 28, and located adjacent to the face plate 24. 48 is Q-distant from the screen 28 and provides a surface for receiving and mounting the metal thin film shadow mask 50 with tensile force. The pattern of fluorescence matches the pattern of the openings in the mask 50. The apertures shown are greatly enlarged for illustrative purposes, and in high resolution color tubes, the mask has many apertures, such as 750,000 openings with an aperture diameter of about 5 mils on average. As is known in the art, the thin-film shadow mask acts as a parallax barrier that ensures each beamlet is configured by three beam hands only for the color-selective electrode or assigned fluorescence deposition on the screen. .

The potential-dominant axis of the cube 20 is indicated by reference numeral 56. Magnetic shield 58 is shown enclosed within funnel 34. The high voltage for tube action is indicated as being applied to the conductive coating 60 on the inner plane of the funnel 34 by an anode button 62 connected to the high voltage conductor 64.

The neck 66 of the tube 20 is marked as providing three discontinuous electron beams 70, 72, 74 for generating a raised red, green and blue light emitting fluorescent component respectively on the screen 28. It is shown surrounding the electron gun 68 on a line. Yoke 76 is provided to receive the signal being scanned and to scan the beams 70, 72, 74 passing through the screen 28. Electrical conductor 78 is located in an opening in shield 58 and is in contact with conductive coating 60 providing a high voltage connection between coating 60 and screen 28 and shadow mask 50.

The two main elements, marked in-proess, are marked and described below. One of them is the shadow mask shown in FIG. 2, which shadow mask 86 uses the mask as an optical stencil to coincide with the pattern of fluorescence deposited on the screen of the faceplate in the center region 104 of the opening. ). The central field 104 is shown surrounded by a section 106 without holes. The peripheral device is engaged by tensioning the frame during the mask tension and clamping process and is removed in a later process.

In-process faceplate 108 is shown in FIG. 3 as having a centrally located screen area 112 on the inner surface to receive the selected fluorescent pattern in the next operation. The funnel sealing surface 113 is indicated around the screen 112. The framed shadow mask support structure 114 is marked as being secured on opposite sides of the screen 112. The structure provides a surface 115 for receiving and mounting the thin film shadow mask under tension by Q distance from the screen.

The process according to the invention provides a step of providing an open thin film shadow mask 86 characterized by being composed of an nickel-iron alloy characterized by being made of a nickel-iron alloy and a face plate under tension in conformity with the fluorescent screen. Securing the mask 86 to the mask support structure 114 of 108. This treatment is also characterized by placing the mask 86 under thermal cycle to partially anneal the mask to some state in the mask with the mask having magnetic and mechanical properties.

In accordance with the present invention, a class of nickel-iron alloys containing small amounts of certain alloying reagents, when heat treated and cooled in a controlled state, when assembled into thin films, are known alloys for use with tensioned thin film shadow masks. Provides materials with mechanical and magnetic properties not found in

The good properties achieved by the method of the present invention are as follows: the alloy thin film is at least about 80 ksi, preferably at least about 100 ksi, most preferably to withstand the tensile load applied to the thin film when used as a tensile thin film shadow mask. Has a yield strength of at least about 150 ksi (0.2 percent offset). This yield strength combines magnetic properties of high permeability and low coercivity. The transmittance is about 6,000 preferably greater than about 10,000, most preferably greater than 100,000, and the degree of coercivity does not exceed about 2.5 Hertz, preferably about 0.5 Herst or less.

Particular examples of alloys made from thin film shadow masks tensile in response to the heat treatment according to the present invention are known nickel-iron-molybdenum alloys sold under the trade names HyMu 80, YeP-C and Molly-Malloy. These alloys contain about 80 percent nickel, 4 percent molybdenum, the remaining iron and incidental impurities. In the rolled and fully cured state, the 80Ni-4Mo-Fe thin film has high yield strength, typically 155 to 160 ksi, but has poor magnetic properties, for example less than 3,000 transmissions.

To provide good magnetic properties for use in tape recorder heads, the material is typically annealed at 1120 degrees Celsius for 2 to 4 hours, cooling the furnace to 600 degrees Celsius. A sufficiently annealed alloy thin film has good magnetic properties but also poor mechanical properties. The transmittance can be as high as 300,000. However, the yield strength is in the range of 20 to 40 ksi, making the alloy obviously unsuitable for use as a tensioned thin film shadow mask when sufficiently annealed.

However, when the 80Ni-4Mo-Fe alloy thin film is partially annealed according to the process of the present invention, it unexpectedly shows excellent properties as a material for producing a tensioned thin film shadow mask. As a result of this cycle of heating and cooling according to the invention, the mechanical properties of the alloy are retained while the magnetic properties are improved to the extent necessary for use as a thin film shadow mask.

Surprisingly, the magnetic properties of the 80Ni-4Mo-Fe thin film when treated in accordance with the present invention are significantly improved when the thin film is placed under tension. For example, after heat treatment and conditioning according to the present invention, an unstretched 80Ni-4Mo-Fe thin film with a thickness of 1 mil has a transmittance of 60,000. When the same thin film is placed under a tension of about 60 Newtons / cm, its transmittance is increased to 100,000. The same material typically does not cause a high permeability change under tension when in the fully cured state. As a result of the increased transmittance, the amount of beam misregistration caused by the magnetic field of a 1 mil thick 80Ni-4Mo-Fe thin film when treated in accordance with the present invention is much less than a 1 mil thick AK-steel film.

With respect to the alloy composition, the nickel-iron alloy may comprise weight-percent nickel between about 30 and 85, weight-percent molybdenum between about 0 and 5 of molybdenum, and weight-percent between one and more vanadium, titanium between 0 and 2 , Hafnium and niobium, the remainder consisting of iron and ancillary impurities such as carbon, chromium, silicon, sulfur, copper and manganese. Typically, the incidental impurities combined do not exceed 1.0 percent. Preferably, the alloy consists of weight-percent nickel between about 75 and 85, weight-percent molybdenum between about 3 and 5 of molybdenum, and the remainder iron and incident impurities. In one particular embodiment, the alloy consists of about 80 weight percent nickel and about 4 weight percent molybdenum, the remainder being iron and incident impurities.

Partial annealing of good materials can be achieved according to the additional features of the present invention as a discontinuous step prior to installing the mask on the mask support structure secured by the faceplate. In order to advantageously combine mechanical and magnetic properties, the thin film must be subjected to a prescribed procedure of heat treatment and slow cooling in accordance with the present invention to provide a thin film according to a preferred combination of magnetic and mechanical properties.

In a conventional method according to the invention, a group of twelve fully-cured opening masks of the configuration shown in FIG. 2 are stacked for insertion into an oven. In the process according to the invention, providing each of the stacked masks in a heat cycle to partially heat the masks to produce good magnetic and mechanical properties, provided that the mask alloy is substantially at least about 30 minutes, preferably about 45 minutes. The mask is heated to a temperature of at least about 400 degrees Celsius and below to form a solid solution, so that the alloy from which the mask is formed is almost at a cooling rate of about 5 degrees Celsius per minute or less, preferably about 3 degrees per minute or less. Gradually cooling the mask to a temperature to be recrystallized, and securing the mask to a mask support structure attached to or integral with the faceplate when the mask is under tension and coincides with the phosphor screen. . For example, the mask is heated to a temperature between about 400 degrees Celsius and 700 degrees Celsius for a period between about 30 minutes and 60 minutes. The mask then has a material of less than about 5 degrees Celsius per minute, preferably about every minute It is slowly cooled to a temperature that is almost recrystallized at a cooling rate between 3 degrees Celsius or less, most preferably about 2 degrees Celsius and 3 degrees per minute. Longer heat treatments are acceptable, but do not improve properties. Heat treatments that are treated at the indicated temperatures and cooled or air cooled at rates above 5 degrees Celsius per minute result in thin films with undesirable mechanical properties. While no specific theory is intended to be applied, heat treatment at temperatures below the annealing temperature and subsequent slow cooling cause the Ni ₃ Fe to be ordered regularly as intergranular precipitates.

The heating of the assembly and the thin film and the slow rate cooling of the assembly and the thin film according to the present invention partially heat the thin film mask to yield a yield strength of at least 80 ksi, a transmittance of at least about 6,000, a degree of penetration of less than about 2.5 ersted, a faceplate (glass) The expansion coefficient above the coefficient of thermal expansion occurs. In accordance with the process described above, the mask has a yield strength of at least about 150 ksi, a transmittance of at least about 100,000, and a coercivity of at most about 1.0. The thin film can withstand tensile loads in excess of about 65 Newtons / centimeter, possibly greater than 75 Newtons / centimeter.

The heat treatment and slow cooling treatment of the mask described below outline the treatment steps of the frit sealing cathode ray tube and the sealing of the funnel and face plate of the manufacturing process.

According to the initial setup of the process of the present invention, the heating and cooling conditions in which the tensioned mask is provided during the frit cycle are achieved without the above-described improvement of the alloying properties requiring the above-mentioned heating treatment and slow cooling treatment. The properties of the mask are not as good as achieved when the mask material is heated to the desired temperature of 500 to 600 degrees Celsius. However, if the brightness and resolution required for the cathode ray tube are not high, the 80-Ni-4Mo-Fe tensile mask in-place in the frit cycle is slowly heated to about 435 degrees Celsius, then about 5 degrees Celsius every minute. At rates below degrees, it has been determined that a complete mask with the desired mechanical and magnetic properties is provided by slowly cooling at rates between about 2 degrees Celsius and 3 degrees per minute, which is preferably the cooling rate in the frit cycle.

For example, an untreated tensile thin film mask is placed under a tension of 30 Newtons / cm, and when operated through a frit cycle, yield strength between about 150 ksi and 160 ksi, transmittance between about 60,000 and about 100,000, about 0.4 The degree of coercivity below Erstedt is achieved. The beam miswriting is slightly higher than that obtained when the thin film is heat treated, but below the predetermined limit.

Partial annealing according to the invention can be achieved as a result during the thermal cycle in the process of sealing the tube. This process is described below.

As shown in FIG. 3, the shadow mask support structure 114 fails on the inner surface 110 of the faceplate 108 between the screen area 112 and the peripheral sealing area 113 which is the funnel sealing surface 113. do. Mask support structure 114 provides a surface 115 for receiving and supporting a tensile thin film shadow mask. The mask support structure 114 is made of, for example, a stainless steel metal alloy. Attachment of the support structure is preferably achieved by an opaque frit.

Nickel-iron alloys include: weight-percent nickel between about 30 and 85, weight-percent molybdenum between about 0 and 5, weight-percent by one or more vanadium, titanium, hafnium and niobium, and the remaining iron And incidental impurities such as carbon, chromium, silicon, sulfur, copper and manganese. Typically, the incidental impurities combined do not exceed 1.0 percent. Preferably, according to the present invention, the alloy consists of weight-percent nickel between about 75 and 85, weight-percent molybdenum between about 3 and 5 of molybdenum, the remaining iron and incidental impurities. Preferably the alloy consists of about 80 weight-percent nickel and about 4 weight-percent molybdenum and the remaining iron and incidental impurities.

The alloy according to the invention is formed in a thin film having a thickness of about 0.001 inches or less.

The central area 112 of the thin film is opened to form a thin film mask 108 that is sized to match the screen area 112 for color selection. The opening of the mask is achieved by a photo-etching process in which photosensitive resist is applied to the thin film. The resist cures due to exposure to light except in areas where openings are defined. The exposed metal defining the openings is etched.

The thin film mask is then tensioned in a tension frame for a tension of at least about 25 Newtons / cm. The membrane is stretched by enclosing the membrane between two press plates heated to 360 degrees Celsius for 1 minute, clamped in a tension frame, and air cooled to provide a tensioned membrane with a length and width greater than that of the faceplate. Patterns of red light, green light and blue light phosphorescent deposits are optically screened on screen area 112. The optical screen treatment involves matching a thin film of the phosphor screen area by matching the face plate and the tension frame.

The thin film constituting the mask 86 is secured to a mask support structure 114 having an opening in the mask that matches the pattern of phosphorescent deposits on the screen area 112. The means for securing the mask to the mask support structure is achieved by receiving with a laser beam, and excess mask material is removed by the same beam. As long as the faceplate 108 and the tensioned thin film shadow mask 86 are interconnected to the mask support structure with interconnects, the thermal coefficients of expansion of the alloy thin films are about 12 × 10 ⁻⁶ and 14 × ^{10 −6} in / in degrees Celsius. It is almost identical to the glass faceplate with the coefficient of expansion between degrees. This is necessary because of the relatively high temperatures that the faceplates and masks provide in the cathode ray tube manufacturing process. Slightly larger coefficients of expansion than faceplates are allowed, but smaller coefficients of expansion than faceplates can cause mask failure in the manufacturing process.

4 and 5 illustrate the use of the funnel reference and frit fixture 186 to mate the funnel 188 and faceplate 108 to form a faceplate-funnel assembly. The face plate 108 is installed downward on the surface 190 of the fixture 186. The funnel 188 is located on the faceplate 108 and with the funnel sealing surface 113 shown around the screen area 112 where the pattern of phosphor 187 is deposited as a result of the previous screen operation. Contact. Referring to FIG. 4, three posts 192, 193, and 194 align the funnel and faceplate. 5 is a detailed view of the interface between the post 194, faceplate 108 and funnel 188. Flat 117c on faceplate 108 aligns with reference area C on funnel 188. The tensioned shadow mask 86 is preferably installed on the shadow mask support structure 114.

The post 194 has two reference points 196 and 198 for positioning the funnel 188 with reference to the faceplate 108. Reference points 196 and 198 preferably include buttons of carbon because they must be able to withstand the effects of elevated oven temperatures generated during the frit cycle.

Paste-type opaque frit is applied to the peripheral sealing region of the faceplate 108 for storing the funnel 188, which is the funnel sealing region 113. Faceplate 108 then mates with funnel 188 to form a faceplate-funnel assembly. A frit, indicated by reference numeral 200 in FIG. 5, is, for example, frit number CV-130 manufactured by Owens-Illinois, Toledo, Ohio.

The faceplate-funnel assembly is heated to a temperature effective to make the frit opaque and permanently attach the funnel to the faceplate, and then cool. The fusing process of the funnel to the faceplate is carried out under what is referred to as a frit cycle. In a typical frit cycle, the faceplate and funnel to which the recognized thin film mask is adhered is slowly heated to 435 degrees Celsius and then cooled to room temperature or slightly higher, in a period of 3 to 3.5 hours. The thin film is cooled to a temperature at which the alloy is recrystallized at a cooling rate between about 5 degrees Celsius or less per minute, preferably about 3 degrees Celsius or less per minute, and most preferably between about 2 degrees Celsius and 3 degrees per minute.

The heating of the assembly and the thin film and the slow cooling rate of the assembly and the thin film according to the present invention partially heat the thin film mask during the frit cycle, resulting in the mechanical and magnetic properties described above.

Test results in support of the concept according to the invention are summarized in the following examples.

The 80Ni-4Mo-Fe cold rolled thin film is 1 mil thick. In the housed state, the thin film has a transmittance of 3000, a coercivity of 2.2 Hersted, and a yield strength of 156 ksi.

The thin film is heat-treated in a hydrogen atmosphere dried at 500 degrees Celsius for 60, and cooled to 200 degrees Celsius at a cooling rate of 3 degrees Celsius every minute. The heat treatment results in a thin film having a yield strength of 192 ksi, a 60,000 transmittance, a coercivity of 0.31 Ersted, and an expansion coefficient of 13 x ^10-6 in / in.

Example 2

The 42Ni-Fe cold rolled thin film 1 has a thickness of 1 mil. In the housed state, the thin film has a transmittance of 3000 transmittance, a magnetic field of 4.0 Hersted and a yield strength of 110 ksi.

The thin film is heat treated in a hydrogen furnace, dried at 600 degrees Celsius for 2 hours, and cooled to 200 degrees Celsius or less at a cooling rate of 2 degrees Celsius per minute. The heat treated and slow cooled thin film has a yield strength of 80 ksi, a transmittance of 90,000 and a magnetic field of 1.1 Hersted.

Example 3

The 49Ni-Fe thin film 1 has a thickness of 1 mil. In the housed state, the thin film has a 3200 transmittance, a Young's coercivity and a yield strength of 115 ksi.

After heat treatment and slow cooling according to Example I, the thin film had a yield strength of 85 ksi, a transmittance of 10,000 and a magnetic field of 0.4 Hersted.

Example 4

The 49Ni-4Mo-Fe thin film 1 is 1 mil in thickness in the stored state, and has similar physical and magnetic properties to the thin film of Example I. After heat treatment and gradual cooling according to Example I, the thin film had a 20,000 transmittance, 0.3 Ested coercivity and a yield strength of 160 ksi.

Example 5

The 79Ni-2Mo-Fe thin film 1 is 1 mil in thickness in the stored state, and has similar physical and magnetic properties to the thin film of Example I. After heat treatment and gradual cooling in accordance with Example I, the thin film has a transmittance of 30,000, a coercive force of 0.3 Hersted, and a yield strength of 160 ksi.

Example 6

The 79Ni-2V-1Ti thin film 1 is 1 mil in thickness in the stored state, and has a physical and magnetic property similar to that of the thin film of Example I. After heat treatment and gradual cooling according to Example I, the thin film has a transmittance of 20,000, a coercive force of 0.3 Hersted, and a yield strength of 170 ksi.

Example 7

The 79Ni-4Mo-Fe thin film 1 is 1 mil in thickness in the stored state, and has similar physical and magnetic properties as the thin film of Example I after heat treatment and slow cooling through a conventional frit cycle. The frit cycle consists of a furnace with a peak temperature of about 435 degrees Celsius. The total time duration for the sample to pass from the inlet to the outlet of the furnace is about 3.5 hours. The thin film has a transmittance of about 60,000 transmittances, a coercivity of about 0.4 Elste and a yield strength of about 155 ksi.

The thin film shadow masks according to the invention used in tensioned thin film color cathode ray tubes or faceplate assemblies for such tubes are well formed from alloys, the alloys having a weight-percentage of between about 30 and 85 nickel, about molybdenum It consists of a weight-percent molybdenum between 0 and 5, one or more vanadium, titanium, hafnium and niobium in a weight-percentage between 0 and 2, yield strength of 80 ksi or more, transmittance of about 6,000 or more, , Has a coefficient of thermal expansion above the face plate. In addition, the mask is under a tensile force of at least about 25 Newtons / centimeter when the tube is provided at ambient temperature. The alloy according to the present invention has a yield strength of at least about 150 ksi, a transmittance of at least about 10,000, and a magnetic field of about 1.0 or less. Regarding the contents of the mask alloy, more specifically, the contents consist of weight-percent nickel between about 75 and 85, weight-percent molybdenum between about 3 and 5, remaining iron and incidental impurities, and preferably Silver consists of about 80 weight-percent nickel, about 4 weight-percent molybdenum, and the remaining iron and incidental incompatibilities.

Claims (11)

For use in a tensioned thin film color cathode ray tube comprising a flat face plate and a thin film mask mounted on the flat face in a tensioned state, the thin film mask being between about 30 and 85 weight-percent nickel, about 0 and An alloy containing between 0 and 2 weight percent alloy reagent selected from the group consisting of weight percent percent molybdenum, vanadium, titanium, hafnium, niobium and mixtures thereof, and the remaining iron and incidental impurities Wherein the alloy is a thin film shadow mask having a coefficient of thermal expansion that is not less than a coefficient of thermal expansion of the faceplate of the cathode ray tube, wherein the alloy comprises between about 75 and 85 weight percent of nickel and about 3 and 5 weight- A thin-film shadow mask comprising percent molybdenum. The thin film shadow mask of claim 1, wherein the alloy has a yield strength of at least 80 ksi, a permeability of at least about 6000, and a coercivity of less than about 2.5 Herstets. 3. The thin film shadow mask of claim 1 or 2, wherein the mask is under a tensile force of at least about 25 Newtons / cm when the cathode ray tube is at ambient temperature. 3. The thin film shadow mask of claim 1 or 2, wherein the alloy of the mask has a yield strength of at least about 150 ksi and a transmittance of at most about 1.0 erstet or less. The thin film shadow mask of claim 1, wherein the alloy of the mask together comprises about 80% by weight nickel, about 4% by weight molybdenum, the remaining iron, and ancillary fluoride. A method of making a thin film shadow mask for a tensile mask collar cathode ray tube comprising a face plate having a phosphor screen on an inner surface and a support structure for supporting an adjacent stretched thin film shadow mask, wherein a weight-percent between about 75 and 85 Nickel; Weight-percent molybdenum between about 0 and 5, weight-percent vanadium between about 0 and 2 weight-percent titanium between about 0 and 2, weight-percent hafnium between about 0 and 2, and about 0 and At least one of the weight-percent niobium between two; Providing a cured nickel-iron alloy thin film comprising remaining and iron and incidental impurities, and heat treating the thin film for a period of at least about 30 minutes at a temperature of about 400 ° C. lower than the temperature at which the alloy forms a solid solution. And controlling the cooling rate of the thin film from the temperature to a temperature at which the alloy is recrystallized to provide a thin film having a yield strength of greater than about 80 ksi, a permeability of greater than 6000, and a magnetic field of less than 2.5 Hersted, Heat treating the cured thin film under conditions of achieving good magnetic shielding properties while maintaining the strength properties of the cured material sufficient to withstand normal operating mask tensile levels, applying a tensile force to the thin film, and And securing a thin film to the support structure. Mask manufacturing method. 13. The faceplate of claim 12, wherein the faceplate has a centrally positioned phosphor screen area surrounded by a peripheral sealing area for mating with a funnel on an inner surface, and a shadow mask comprises the faceplate between the peripheral sealing area and the screen area. Fixed in a framed shadow mask-supporting structure on an inner surface, the process comprising forming the alloy with a thin film, forming the thin film mask to a size that matches the size of the screen area for color selection; Opening the central region of the thin film, tensioning the thin film with a tensile force of at least about 25 Newtons / cm, optical screening a pattern of red, green and blue emitting tensile deposits on the screen area; By matching the face plate and the tension frame, the phosphor screen area and the thin film Mating multiple layers, applying a tensile force to the thin film mask, securing the thin film mask to the mask-supporting structure with the phosphorescent deposits of the pattern and the opening coincident, paste to receive a funnel Applying an opaque frit of type to the peripheral sealing region, mating the funnel with the faceplate to form a faceplate funnel assembly, making the frit opaque and permanently attaching the funnel to the faceplate Heating the assembly to a temperature, and cooling the assembly to a cooling rate of less than about 3 degrees Celsius and less than 5 degrees Celsius per minute to obtain an expansion coefficient above the coefficient of thermal expansion of the faceplate. Mask manufacturing method. A thin film shadow mask fabrication process for use in a tensioned mask color cathode ray tube that preferably combines physical and magnetic properties, comprising: between about 30 and 85 weight-percent nickel, between about 0 and 5 weight-percent molybdenum, 0 And providing a thin film mask consisting of an alloy containing at least one vanadium, titanium, hafnium and niobium between 2% by weight and the remaining iron and incidental impurities, about 400 degrees Celsius and about 700 degrees Celsius before and after installation in the tube. Heating the mask for a period between about 30 minutes and 2 hours at a temperature above and above the temperature at which the alloy forms at least a solid solution, and from about 3 degrees Celsius per minute to a temperature at which the alloy is substantially recrystallized from the temperature. Thin-film shadow comprising the step of slowly cooling the alloy at a cooling rate of less than 5 degrees Mask manufacturing method. 19. The method of claim 18, wherein the thin film mask has a yield strength of at least about 150 ksi, a permeability of at least about 10,000, and a coercivity of less than 1.0 Hersted. The method of claim 12, wherein the cooling rate is 50 ° C. or less, preferably 3 ° C. or less. 13. The method of claim 12, wherein the thin film is placed under a tensile force of at least 25 Newtons / cm.

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