JPS6222356A - Picture tube - Google Patents

Abstract

PURPOSE:To achieve a low PD level and produce a bright clear flat picture plane by using an intratubular part which is made by forming a black oxide film of spinel structure over the surface of an alloy base having a special composition with a layer containing a higher concentration of chromium than the alloy base interposed. CONSTITUTION:The picture tube of this invention includes an intratubular part which is made by forming a black oxide film of spinel structure containing chromium, nickel and iron over the surface of an alloy base composed of iron, 25-45wt% nickel and 0.3-10wt% chromium with a layer containing a higher concentration of chromium than the alloy base interposed. The content of Ni is adjusted to 25-45wt% in order to adjust the thermal expansion coefficient of the alloy base to at most 90X10<-7>/ deg.C. Ni contents of outside this range can not achieve a sufficiently low thermal expansion coefficient of the alloy base. Cr increases the thermal expansion coefficient of an Ni-Fe alloy and reduces its 0.2% yield strength which determines the moldability of the alloy. Since a CR content of 0.5 or higher suppresses the 0.2% yield strength of the alloy and a Cr content exceeding 10wt% increases the 0.2% yield strength, the content of Cr is restricted to 0.3-10wt%. The black film formed over the surface of the alloy base achieves improved thermal radiation.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is directed to improving the display image quality by using tube parts such as shadow masks, frames, inner shields, and bimetals that have good moldability and excellent thermal characteristics. Concerning high picture tubes.

[Technical background of the invention and its problems] A picture tube generally has the configuration shown in FIG.

That is, the neck portion 2 constituting the negative end of the glass envelope 1 is provided with, for example, an in-line electron gun 3, and the face of the other end of the glass envelope 1 facing the electron gun 3 is provided. A phosphor screen 5 in which red, blue, and green phosphors are arranged in sections is provided in the section 4.A shadow mask 6 having a large number of beam apertures is disposed in the vicinity of the phosphor screen 5 and facing the phosphor screen 5. This shadow mask 6 is attached to a frame 7 via a fastener 8, and an inner shield 9 is attached to the frame 7 to block the influence of earth's magnetic field.

However, in the color picture tube configured in this manner, the electron beam 11 emitted from the electron gun 3 is deflected under deflection control by a deflection device 10 provided at the base of the neck portion 2. The light passes through the apertures of the shadow mask 6 and hits the fluorescent screen 5 to generate fluorescence to form a color image.

Incidentally, the shadow mask 6, frame 7, and inner shield 9 are made of rimmed steel or AJ2 quilt, which have better etching and formability than conventional ones, and which are easy to form an oxide film on the surface that contributes to reducing reflection of electron beams. It is made of steel or other materials. However, in recent years, in order to respond to various new media, the quality of color picture tubes has improved,
In other words, so-called easy visibility and ultra-fine display images are required, and problems have arisen when using the shadow mask 6, frame 7, and inner shield 9 made of the above-mentioned rimmed steel or A1 killed steel.

That is, during operation of the color picture tube, the temperature of each of the above-mentioned members rises to 30 to 100 DEG C., and for example, so-called doming occurs due to distortion in the molded shape of the shadow mask due to thermal expansion. As a result, a shift occurs in the relative positional relationship between the shadow mask and the phosphor screen, resulting in a color shift called purity drift (PD). In particular, in high-quality color picture tubes, since the aperture diameter and the aperture pitch of the shadow mask are very small, the relative amount of deviation becomes large. The parts are no longer practical. In particular, the above-mentioned problems have occurred particularly in high-curvature color picture tubes that reduce image distortion and reflection of external light.

Therefore, it has been conventionally known to use Ni-Fe alloys with a small coefficient of thermal expansion, such as amber (36Ni-Fe), as a material for forming this type of pipe internal parts.
-25446, JP-A No. 50-58977, JP-A-5
0-68650 etc. However,
This type of Ni--Fe alloy has poor thermal conductivity and not only tends to accumulate heat, but also tends to cause so-called springback, which is a depression from the spherical surface of a normal shadow mask toward the electron gun. Furthermore, when the holes in the shadow mask are formed by etching, there are problems in terms of etching performance and moldability, such as the possibility of unevenness in the diameter of the holes. For this reason, there was a limit to the ability to improve the quality of color picture tubes.

[Object of the Invention] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a screen that is nearly flat, has little color shift, and produces detailed and bright high-quality images. The objective is to provide a picture tube that can be obtained.

[Summary of the Invention] The present invention provides that at least one of the tube internal parts such as a shadow mask, inner shield, frame, and bimetal in a color picture tube contains 25 to 45 wt% of nickel, 0.3 to 10 wt% of chromium, and the balance is iron. A black oxide film with a spinel structure containing chromium, nickel, and iron is formed on the surface of the alloy body having the composition through a chromium concentrated layer having a higher chromium concentration than the inside of the alloy body. This is a characteristic picture tube. As a result, we can obtain tube parts such as shadow masks, inner shields, frames, and bimetals with improved moldability and heat dissipation properties, and use these to obtain bright, flat, and easy-to-see screens with low PD values. This is a realization of a picture tube.

Here, the reason why the above-mentioned old composition amount was set to 25 to 45 wt% is to make its thermal expansion coefficient 90X10-7/'C or less, and if the amount of Ni added is out of the above range, the present invention Therefore, it becomes impossible to obtain a material for pipe internal parts with a low coefficient of thermal expansion. In other words, a clear image with a low PD value cannot be obtained. Furthermore, if the amount of Ni added exceeds 45 wt%, the 0.2% proof stress, which is a measure of the quality of the moldability, increases, and the moldability deteriorates significantly. For example, in the case of a shadow mask, springback occurs, making it difficult to obtain a clear image. At the same time, its improved oxidation resistance makes the blackening treatment normally applied to its surface extremely difficult.

Regarding etching properties, when the amount of Ni increases, fine etching becomes difficult, and the inner walls of the etching holes become so-called rough holes, and a large amount of N1 dissolves in the etching solution, resulting in a decrease in the etching rate. 4B
Problems such as < occur.

Further, Cr increases the coefficient of thermal expansion of the Ni-Fc alloy, but on the other hand, reduces the above-mentioned 0.2% yield strength, and greatly contributes to improving the formability. Therefore, the addition of cr does not cause the P and D values to become worse compared to conventional amber. This is especially true for shadow masks with high curvature (
It plays an important role in improving moldability when molding.

That is, in general, as shown in JP-A-50-58977, when Cr is added to a 36Ni-Fe alloy and it is not annealed above the recrystallization temperature, the crystal grains are fine, so 0.2% at room temperature is added. This results in an increase in yield strength, making it difficult to maintain the curvature as a shadow mask, for example, and the addition of Cr only serves to increase the strength of the material. However, when a specific annealing treatment is applied to the 36N i -Fe alloy to which cr is added as in the present invention, the amount of decrease in proof stress by 0.2% is greater than that of the 36N i -Fe alloy (amber) without the addition of Cryfi. The number of cases increases significantly.

In other words, Cr contained in the material plays an important role in significantly reducing the 0.2% yield strength of the material during the annealing process.

Figure 2 shows the annealing temperatures of 0 and 2 for the 36N i -Fe alloy to which 6 wt% Cr is added, which is the material according to the present invention.
The change in % proof stress is shown as characteristic A, and characteristic B is the change in 0 and 2% proof stress with respect to annealing temperature in a 3614 i -Fe alloy without the addition of cr, shown for comparison. As shown in this figure, the material for pipe internal parts according to the present invention has a higher 0.2% proof stress at room temperature, but
When annealed at temperatures above ()°C, the temperature is 0.
2% yield strength becomes sufficiently low. For example 1000~1200℃
When annealed in vacuum at
．． 2% yield strength is 12! ? /m, but in the case of conventional Cr-free products, the 0.2% yield strength is 22Kg/m.
It is large, about IIIA. Therefore, from this fact as well, it can be seen that the addition of Cr greatly contributes to the reduction of the 0.2% proof stress during annealing. Incidentally, there is Hn which exhibits the same effect as C.

Therefore, it is possible to partially replace Cr with Hrl up to 5 wt%, but preferably up to 2 wt%. This addition of Cr is also effective for super amber containing 30 to 35% old and up to about 10% CO. Therefore, in the present invention, C may be used as necessary.

(preferably 0.2 to 7 wt%) may be added.

By the way, a color picture tube was assembled using a shadow mask made by hydrogen annealing a flat mask made of the material shown in characteristic A above at 800°C and oxidizing it with steam to form a black oxide film on the surface, and the color picture tube was assembled for 3 minutes. When the PD value was measured, it showed a small value of 95-. On the other hand, when similar measurements were taken using a conventional shadow mask using amber that had undergone similar heat treatment, the springback of the shadow mask was significant and the color unevenness was severe, so the PD value was measured. I couldn't.

By the way, if the amount of Cr added is less than 0.3 wt%,
As with the 368i-Fe alloy without the addition of cr, the annealing temperature was set to 1.
Even if it is as high as 200℃, its 0.2% yield strength is 20Krj
/In! It cannot be less than 7. In addition, if the amount added exceeds 10wt%, the coefficient of thermal expansion will be 90X10-7.
/"C or higher, causing color shift, making it unsuitable for use in high-definition color picture tubes. Also, if the amount of Cr added exceeds iowt%, Crz03 is added to the surface.
A protective film is easily formed, which reduces the surface blackening rate.
etc., causing inconvenience in the blackening process.

That is, FIG. 3 shows the change characteristic C of the 0.2% proof stress and the change in the coefficient of thermal expansion when a flat mask formed using the material for pipe internal parts according to the present invention is annealed at 1000°C in hydrogen. If the amount of Cr added is 0.5 to 1 swt%, as indicated by the above-mentioned Cr addition ω as a parameter, the 0.2% yield strength is 22Ng/Ir by annealing.
It can be seen that springback can be prevented by suppressing the IA to below. Furthermore, if the amount of C exceeds 10 wt%,
This not only causes an increase in the 0.2 proof stress but also an increase in the coefficient of thermal expansion, which causes a drift in the PD value. Therefore, as mentioned above, it is necessary to limit the amount of Cr added to 0.3 to 10 wt%.

Materials with such alloy compositions are processed to manufacture tube internal parts such as shadow masks, and the blackened film formed on the surface of the material is important in improving its heat dissipation properties. It plays a major role in lowering the PD value of color picture tubes. This heat dissipation property is determined by the degree of blackness and the roughness of the surface, and the blackened film according to the present invention is excellent in the following points.

That is, a spinel structure containing chromium, nickel and iron (C
rxNivFe3-x-yos (0<X, Y<3))
The black oxide film differs from the black oxide film formed on conventional A1 killed steel and Yarimudo steel, and has a spinel-type oxide structure in which some of the Fe sites are replaced with Cr and Ni. This black oxide film hardly contains gas or voids due to pores inside the film, and has excellent adhesion to the material. Furthermore, because of its high hardness, it is also effective in preventing howling caused by vibration.

The thickness of the blackened film is preferably 0.3 to 5 u. This is 0.
If it is 3- or less, the thermal emissivity is 0.2 or less (a perfect black body is 1
．． 0), some red rust may occur while saving the shadow mask, and 5JJI! This is because the blackened film may peel off if the amount exceeds this value.

Further, in the present invention, this black oxide film is formed on the element body via a chromium concentrated layer. This chromium-concentrated layer has a higher chromium concentration than the inside of the alloy body, and by forming this layer, the adhesion of the spinel structure coating is improved. The effect appears with a small amount of concentration, but if the chromium concentration in the alloy body is no, and the chromium concentration in the chromium concentrated layer is 0,
When set to 1, 10no≧n1≧1.2n.

It becomes noticeable when the relationship is satisfied. If the Cr concentration becomes too high, the growth of a black oxide film will be prevented. Also n
The same holds true even if l exceeds 50 wt%.

Roughly speaking, the thickness of this concentrated layer (a1) is preferably about 10 or less than that of the black oxide film (a O), because if it is too thick, the adhesion will actually decrease and the heat dissipation will also decrease. . The lower limit is not particularly stipulated, but at least o,
The effect is fully demonstrated at around 14.

Furthermore, since needle-shaped crystals tend to form perpendicular to the mask surface,
The surface area of the surface oxide increases, further improving its thermal emissivity.

Also, Cr x N i y Fe5-x-yos
Even if the unavoidable components enter or dissolve into the material, its properties will not change. This means that 30 to 35
Super amber containing % Ni and up to 7% Co
When r is added, Co dissolves in the blackened film (
Crx Niy COz Fes -X-Y-ZO4,
O<X, Y, Z<3), which can be seen from the fact that the characteristics do not change.

In addition, when the material is one in which a part of Cr is replaced with Hn, the blackened film is Crx Mny Niz Fe3-X-
A spinel structure of Y(o 4 is formed, and even in such a case, the same effect is exhibited. However, unlike Cr, Hn is often uniformly dispersed in the oxide film.

Similarly, in the case of Co, (cr, In, Co, N
i, Fe).

It is preferable that the number of particles per 1 m or less. This is Annealing Shun's 0
．． This is because the 2% yield strength increases.

Table 1 shows the relationship between 0.2 proof stress and grain size number at 3wt%C.
36N i -Fe added with r was described. The alloy is annealed.

Table 1 Annealing method For example, when air oxidation or steam oxidation is used to form this blackened film on the surface by wet hydrogen annealing, α-Fe2C)3 is formed on the surface. -FezO3 is thin, e.g. Ni y, Cry
The thickness is 175 or less compared to the thickness of the black oxide film having the spinel structure of Fe3-X-YO4, and there is no particular problem.

Fig. 4 schematically shows the cross-sectional structure of the blackened film described above, and Fig. 5 shows a 4Cr-36Ni-Fe film cold-rolled to a thickness of 0.15#l#1. 1000
After vacuum annealing at ℃ for 1 hour, annealing in steam at 1.05 atm.
An example in which depth direction analysis of each element was performed using an ion microanalyzer on the surface of a material that was blackened at 80° C. for 10 minutes and then at 650° C. for 10 minutes is shown. As you can see from now on, cr
A concentrated layer is observed.

In addition, conventionally, 36
As an example of adding Cr to Ni-Fe alloy, JP-A No. 5
There is No. 9-59861. However, no effort has been made to reduce the yield strength; the material is simply high-strength, and no attempt has been made to reduce the yield strength by 0.2%. Furthermore, as will be explained next, no blackened film is formed on its surface, and in consideration of this point, it can be said that it is completely different from the pipe internal component according to the present invention.

Furthermore, in JP-A No. 50-58977, there is an example of blackening a 36N i -Fe alloy to which Cr is added, but similarly, no efforts have been made to reduce the yield strength, and the blackened film is also difficult to peel off. -It contains a large amount of FelQ3 and is different from that of the present invention.

By the way, when we compared the PD values of color picture tubes assembled using a shadow mask made of the above material with a blackening film formed on its surface having the above composition and a shadow mask without a blackening film, we found that The 3-minute PD value of the one without a film was 120 to 130 JJIII, whereas the PD value of the one with a blackened film was 80.
- It was confirmed that it was small. In other words, this blackened film enhances the heat dissipation effect and is highly effective in suppressing PD. Particularly, the effect of this blackening film is remarkable when forming a flattened shadow mask with a curvature of 900,741 or more.

Furthermore, various unavoidable components are mixed into the alloy. The smaller the amount of C, the better the moldability, so there is no harm in reducing it, but it is usually mixed up to 0.01 wt%.

The smaller the amount of Si, the better the formability, but when annealed in a wet hydrogen atmosphere, it concentrates on the surface and has the function of accelerating the blackening rate during blackening, so 0.02 to 0.3 wt% is appropriate. P,
If S exceeds 1 wt % of O, the alloy will become hard, so it is better to reduce the amount to some extent. ) fn is 0.2 as mentioned earlier
It has the effect of reducing the % proof stress, but the coefficient of thermal expansion becomes worse than when adding Cr, so if a large amount of C is added, Hnl
You can lower it by 1 degree. Hn is usually mixed up to about 6 wt%.

In addition, in the present invention, for example, Fe is the main component, and 25
~45wt% Ni, 0.3~10wt% C'',
Annealing and blackening treatment are performed using an alloy that has formed an austenite structure of 80% or more. This alloy is 2
5~45wt% Ni, 0.3~10wt% C''
, remaining Fe and unavoidable impurities and the alloy are melted and then rolled and annealed.Final cold rolling is carried out at a rolling ratio of 40% or more, preferably 80% or more, at 500 to 1200°C.
, preferably at 900 to 1 ioo°C, followed by adjustment rolling at a rolling rate of 30% or less, preferably 20% or less, and, if necessary, strain relief annealing. Etching properties are a problem with materials for pipe internal parts.
The problem is the grain size and the uniformity of the metal structure. If the cold rolling is performed at a rolling reduction of 40% or less, the metal structure will be difficult to align. Furthermore, if the annealing is performed at a temperature lower than 500°C, the crystal grain size cannot be adjusted because recrystallization does not occur.
When annealing is performed at a temperature exceeding 200°C, there is a problem that the grain size becomes too large. In other words, in order to ensure etching properties, it is necessary to define the temperature range of the annealing as described above. It is therefore desirable to manufacture the material as described above. □Furthermore, if the metal constituting the material for the pipe internal parts has structures such as ferrite, martensite, and austenite, the etching speed of each structure will be different, which may cause pore clogging. Therefore, it is generally desirable to form a single structure, but since the process of forming a single structure may be difficult, it is practically sufficient if the austenite structure accounts for 80% or more.

[Effects of the Invention] As explained above, according to the present invention, a predetermined Ni-Fe
Adding Cr to the alloy system reduces its yield strength by 0.2%,
In addition to improving its moldability, the color picture tube is formed by using parts inside the tube such as a shadow mask, which has a black oxide film with good adhesion on its surface. Can be of quality.

In addition, because of its good moldability, it is possible to effectively obtain an image with little color shift even at the four corners of the screen, and it is possible to suppress color change even in a white image that lasts for a long time. In particular, since it is possible to form a flat screen, it is possible to suppress the curvature of straight-line images, which is effective in displaying bright and high-contrast images. On the other hand, because its strength is high,
There is no risk of imaging caused by low-frequency sound waves from speakers placed close to each other, and effects such as being able to sufficiently withstand mechanical shocks and the like and obtaining images without so-called fluctuations can be achieved.

[Embodiments of the invention] Next, examples of the present invention will be described.

(Example-1) First, the main components were 36% Ni and Fe, and 5wt% cr.
Contains 0 and 0 C and 3i as incidental components, respectively.
An alloy ingot containing 1 wt% of P and 5 wt% of P and oo was prepared, and this ingot was repeatedly annealed and cold worked to produce a plate material with a thickness of 0.13 m. Thereafter, a photoresist was applied to this plate material, and after drying, a film having a slot or dot-shaped reference pattern formed on both sides was brought into close contact with the photoresist, and the photoresist was exposed and developed. This phenomenon causes the unexposed portions of the photoresist to be dissolved and removed. After that, the remaining photoresist was hardened by burning, then etched with a ferric chloride solution, and the remaining resist was removed with a hot alkali to create a flat mask that would serve as the original plate for the shadow mask. .

Thereafter, this flat mask was washed, sheared, vacuum annealed at 10-''torr 11000°C, and pressed to obtain a formed mask with a radius of curvature of 1000 m. This formed mask was treated with acid, washed with trichlene,
After washing with water, 60% 02-Nz in a humid atmosphere.
The mixture was oxidized by heating at 0°C for 10 minutes and at 670°C for 30 minutes. Cr
The concentrated layer is 10 wt% cr and 0.6-thick, and the blackened film is 1.1-thick.
It was JJIR. Note that the crystal grain size was 1io0 particles/mA.

The shadow mask manufactured in this manner was attached by spot welding to a frame manufactured by a similar method, and this was attached to a panel via a bimetal.

Then, after applying red, blue, and green phosphors to match the holes in the shadow mask, M vapor deposition, and DAG coating, an inner shield was attached, and the funnel at the rear of the envelope with the electron gun and this panel were assembled. A color picture tube was manufactured by connecting the two and evacuating the inside of the tube. Note that the above inner shield was also manufactured using the same material.

(Example-2) The main components are 36% iron and Fe, 2 wt% of Cr, 2 wt% of CO, and C and Si as incidental components.
, oiwt%, and P and S are each 0.005
Flat masks were manufactured in the same manner as in Example 1 using ingots of alloys containing +wt%. Then, this flat mask was annealed in a hydrogen atmosphere at 100°C for 10 minutes at 680°C and 20 minutes at 720°C to obtain a vapor black thickness of 1.8 tan and a grain size of 600 pieces/mtA. Ta.

(Example = 3) The main components are 36% Ni and Fe, and 4wt% Cr,
C and Si as incidental components were o and oi wt%, respectively.
A flat mask was fabricated in the same manner as in Example 1 using an alloy ingot containing 0,005 wt% of P and S, respectively. Then, this flat mask was hydrogen-annealed at 800° C. and blackened under the same conditions as in Example 2 to obtain a shadow mask, which was used to complete a color picture tube. Note that the concentration layer of C was 0.5-5-1B%, the blackened film was 1.8%, and the crystal grain size was 2100/-.

As a result of examining the PD values at the four corners of each of the color picture tubes of Examples 1 to 3 obtained in this way, it was found that the PD value was as small as about 80-tan, compared to about 100 for the conventional one. showed that. In addition, the time it takes to return to the original normal state after PD occurs is about half (about 2 minutes and 30 seconds) compared to conventional methods. Detailed, high-quality images were obtained.

In addition, although the formation of a shadow mask was explained here as an example,
It is also possible to obtain a color picture tube by similarly manufacturing the inner shield, frame, bimetal, etc. The count,
The present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

Fig. 1 shows the schematic structure of a color picture tube, Fig. 2 shows the change in 0 and 2% proof stress with respect to annealing temperature, and Fig. 3 shows the coefficient of thermal expansion and 0.2 proof stress with respect to the amount of Cr added. Figure 4 is a schematic cross-sectional view of the blackened film, and Figure 5 is a diagram showing the concentration of each element measured by an ion microanalyzer. 1... Envelope, 3... Electron gun, 6... Shadow mask, 7... Frame, 9... Inner shield. Agent Patent Attorney Yudo Nori Chika Kikuo Takehana No. 1 Figure Yakiboard M (・C) No. 2 Diagram Outside Shaku Calling Section (Ylori・C) 0.2% Yield Strength (Ku/mrnri No. 4 figure

Claims (4)

[Claims] (1) Nickel 25-45wt%, chromium 0.3-10
A black oxide film with a spinel structure containing chromium, nickel, and iron is formed on the surface of the alloy body containing chromium, nickel, and iron, with a chromium concentration layer having a higher chromium concentration than the inside of the alloy body. A picture tube characterized by using tube internal parts. (2) Average chromium concentration in the chromium enriched layer (n_1)
is 50wt% or less and satisfies the following relationship with respect to the chromium concentration (n_0) in the alloy body: 10n_0≧n_1≧1.2n_0
Picture tube as described in section. (3) The picture tube according to claim 1, wherein the thickness (a_1) of the chromium concentrated layer satisfies the following relationship: a_1≦3/4·a_0 with respect to the thickness (a_0) of the black oxide film. (4) The crystal grain size inside the element body is 9000 pieces/1mm^
2. The picture tube according to claim 1, wherein the picture tube is 2 or less.