JPS6273531A - Color picture tube - Google Patents

Abstract

PURPOSE:To obtain an almost flat screen, and a delicate, bright, and a high quality picture with little color unevenness, by specifying the quality of parts in a picture tube. CONSTITUTION:At least one of the parts in a picture tube including a shadow mask, an inner shield, a frame, and bimetals is formed of an alloy containing mainly Fe with 25-45wt% of Ni, 0.03-10wt% of Cr, and 0.002-0.01wt% of N and unavoidable impurities. The reason of containing 25-45wt% of Ni is to restrict the rate of thermal expansion below 90X10<-7>/ deg.C, and the addition of Cr is also for the same reason. N prevents the generation of coarse crystalline particles and reduces an uneven expansion of parts in forming, but its content more than 0.01wt% will make crystalline particles too small, resulting in an increased resistivity or reduced extension in forming. In such a composition, a low PD value, bright, flat, and plain picture can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is directed to improving 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 color picture tubes.

[Technical background of the invention and its problems]

A color picture tube generally has the configuration shown in FIG. The face portion 4 at the other end of the glass envelope 1 facing the electron gun 3 is provided with a fluorescent surface 5 in which red, blue, and green phosphors are arranged in sections.

A shadow mask 6 having a large number of beam apertures is disposed close to and facing the fluorescent surface 5. This shadow mask 6 is attached to the frame 7vc via a fastener 8, and an inner shield 9 is attached to the core 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 child gun 3 is deflected under control by a deflection device 10 provided at the base of the neck portion 2. The light beam is deflected, passes through the aperture of the shadow mask 6, and strikes the fluorescent surface 5 to generate fluorescent light to form a color image.

Incidentally, the shadow mask 6, frame 7° inner shield 9 are made of rimmed steel or Al killed steel, which have better etching properties and formability than before, and are easy to form an oxide film on their surfaces that contributes to reducing reflection of electron beams. It is made of steel or other material.

However, in recent years, in order to cope with new media, color picture tubes have been required to have higher quality, that is, display images that are easier to see and extremely fine. Problems have arisen in using the shadow mask 6, frame 7, and inner shield 9.

That is, during operation of the color picture tube, the temperature of each of the above members is 30 to 100'C! This is caused by, for example, distortion in the molded shape of the shadow mask due to its thermal expansion. So-called doming occurs. As a result, a shift occurs in the relative positional relationship between the shadow mask and the fluorescent surface, resulting in a color shift called purity drift (PD). In particular, in high-quality color picture tubes, the aperture diameter and the aperture pitch of the shadow mask are very small, so 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, conventionally, as a material for forming the inner parts of this food,
Ni-Fe alloy with a small coefficient of thermal expansion, such as 7y bar (
36Ni-Fe) is not used, for example, in
-25446, JP-A No. 50-58977, JP-A-5
0-68650 etc. However,
This Ni--Fe alloy has poor thermal conductivity and not only tends to accumulate heat, but also tends to cause dents from the spherical surface of a normal shadow mask toward the electron gun, or so-called springback. For this reason, it has conventionally been necessary to perform vacuum annealing at 1000'O or higher. However, this treatment has the drawback that the crystal grains become coarser and unevenness tends to occur when molded into a normal curved surface.

(Objective of the Invention) The present invention has been made in consideration of the above circumstances, and its purpose is to provide an ultra-fine, bright, high-quality image with a screen that is nearly flat, with little color shift. The object of the present invention is to provide a color picture tube that can obtain a color picture tube.

[Summary of the invention]

In the present invention, at least one of the inner parts such as a shadow mask, an inner shield, a frame, and a bimetal in a color picture tube is mainly composed of Fe containing 25 to 45 wt% of N1 and 0.03 to 10 wt% of Cr.

It is characterized by being formed of an alloy consisting of 0.002 to 0.01 wt% of N and inevitable impurities.

Further, by forming a black oxide film, it is possible to obtain pipe internal parts such as shadow masks, inner shields, frames, bimetals, etc., which have improved formability and heat dissipation properties. By using this, a color picture tube with a low PD value and a bright, flat, easy-to-see image was realized.

Here, the reason why the composition amount of N1 is set to 25 to 45 wt% is to make the thermal expansion coefficient 90×10 /”O or less, and if the amount of N1 added is outside the above range.

It is no longer possible to obtain a material for pipe internal parts with a low coefficient of thermal expansion, which is the object of the present invention. 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, the improved oxidation resistance makes it extremely difficult to carry out the blackening treatment normally applied to the surface.

Regarding etching properties, as Nl:ill increases, fine etching becomes difficult, and the inner wall of the etching hole becomes a so-called rough hole, or Nl enters the etching solution.
The inclusion of a large amount of melt in No. 1 causes problems such as a decrease in the etching rate in No. 7.

Further, Cr increases the thermal expansion coefficient of the Fe-Ni alloy, but on the other hand reduces the above-mentioned 0.21 proof stress, greatly contributing to improving its formability. Therefore, the addition of Cr does not make the PD value worse than that of conventional amber. The temple plays an important role in improving the moldability, especially when obtaining a shadow mask with a high curvature.

That is, generally, Cr is added to a 36Ni-Fe alloy,
If it is not annealed at a temperature above the recrystallization temperature, the crystal grains will be fine and the yield strength will increase by 0.2% at room temperature, making it difficult to maintain the curvature as a shadow mask. This only increases the strength of the material. However, the female mouth of the present invention (3 with Cr added)
When a 6Ni-Fe alloy is subjected to a specific annealing treatment, the reduction in yield strength by 0.2 inches is the same as that of a 36Ni-Fe alloy with no Cr added.
The amount is significantly higher than that of Fe alloy (Antsk). In other words, Cr contained in the material plays an important role in significantly reducing the 0.2 inch yield strength of the material during the annealing process.

Figure 2 shows 6vt'll of Cr, which is the material according to the present invention.
Annealing of p-doped 36Ni-Fe alloy (0
, 2-inch proof stress is shown as characteristic A, and characteristic B is the change in 0- and 2-inch proof stress with respect to annealing temperature in a Cr-free 36Ni-Fe alloy shown for comparison.

As shown in this figure, the 0.2 inch proof stress is higher than that of the material for pipe internal parts according to the present invention at room temperature;
When annealing at SOO''C or above, the V force is sufficiently lowered by 0.2% compared to conventional ones. For example, 1000 to 120
When vacuum annealed at 0°C, the 0.2 inch yield strength of the material for pipe internal parts according to the present invention is 12#/II (but compared to the conventional Cr-free material).

Its 0.2 inch proof stress is as large as 221t9/-. Therefore, from this, it can be seen that the addition of Cr is 0 at the time of annealing.
, it can be seen that this greatly contributes to the reduction of the 2% proof stress.

Incidentally, there is a corridor that exhibits the same effect as this Cr. Therefore, it is also possible to replace a part of Cr with kite. In this case, it is up to about 40 inches of Cr.

By the way, if the amount of Cr added is less than 0.03 wt%, even if the annealing temperature is as high as 1200°C, similar to the 36 Ntl-Fe alloy without Cr addition, the 0.2 inch yield strength will decrease to 22 9/ -Nothing less than that. In addition, if the amount added exceeds 10wt, the coefficient of thermal expansion will be 90XlO-7
/°C or higher causes color shift, making it unsuitable for use in high-definition color picture tubes. Furthermore, if the amount of CrQ added exceeds the IQwt value, a protective film of Cr2O3 is likely to be formed on the surface, causing problems in the dot treatment, such as a decrease in the surface blackening rate.

In addition, conventionally, 36
As an example of adding Cr to Ni-Fe alloy, JP-A-59-
There are issues such as No. 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 inch. Furthermore, as explained next, no blackening film is formed on the surface,
Considering these points, it can be said that this material is completely different from the material for pipe internal parts according to the present invention.

N is an important element that prevents crystal grains from becoming coarser and reduces unevenness during component molding. That is, the inevitable components contained in one alloy are Al, Si, and V.

TI, Zr, Cal? A nitride is formed with IJ'b, Ta, B, or Cr and Mn added as components that lower the yield strength, thereby preventing coarsening of crystal grains during annealing. This is because if the content exceeds the lower limit of 0.002 wt, the crystal grains become too fine, resulting in an increase in yield strength and a decrease in elongation during molding. Due to the addition of N, even during annealing at 1000'O, the crystal grain size is % 6 to 10 as shown in JIS-0551.

In the present invention, Do, which can also contain Co, has the effect of improving etching properties and reducing the coefficient of thermal expansion. As Cr+11 degrees increases,
The crystal grain size is indicated by JIS G0551/f68~12
If the force ζCo is added, etching is difficult unless the grain size is specified. Furthermore, etching is possible even if the crystal orientation of the rolled surface does not necessarily have to be aligned (ioo). Furthermore, the coefficient of thermal expansion decreases as Co increases, and reaches its minimum value when 5 wt of Co is added. The upper limit of this Co content is 10wt1, preferably 0.2 to IQvr
T-chi is available. This is because if the amount is outside this range, the above effects cannot be obtained.

Inclusion of 0 is also effective. Like N, O is an unavoidable metallic element, and it not only forms oxides with elements, but also prevents coarsening of crystal grains.
Provides an oxide film with good adhesion when creating a black oxide film. The upper limit is 0.008 vtS, and if the content is larger than this, not only will the yield strength increase, but also oxides that appear as inclusions during etching will impair etching properties. Preferably it is 0.001 to 0.008 wt%.

The inclusion of C is also effective. Like N, C forms carbides and prevents coarsening of crystal grains. The upper limit is 0.038 wt%, and if it exceeds this amount, the amount of carbides increases, impairing etching properties and increasing yield strength, and the blackened film formed on the surface of the material mentioned above.

It plays an important role in improving its heat dissipation properties and plays a major role in lowering the PD value of color picture tubes. What determines this heat dissipation property is the degree of blackness and the roughness of one surface, and the deteriorated film according to the present invention is excellent in the following points.

That is, the roughness of the black film on one surface depends on the crystal grain size inside the alloy. A cross-section of the black film is shown in Figure 4, and as is clear from the figure, the oxidized film is also exposed outside the crystalline area of the alloy (in the case of 1 soft).In other words, the larger the area of this raised part, the greater the surface area of the blackened film. In the present invention, by intensifying N, C, and 0, the crystal grains of the alloy are made finer and ultimately the heat dissipation properties of the blackened film are improved.The composition of the blackened film is , steam, air at 550-900°0,
When oxidized in carbon dioxide gas, NtxCryFe3
-x-yo4 spinel type oxide film (-o < X
#)'< 3). In the present invention, by adding N and also C10, the blackened film grows quickly, the blackened film becomes thicker, and the heat dissipation property is improved. A slight α− on the surface
Fe304 RαD is produced, but most of it is Nt xCry
This becomes a spinel type layer α3 of Fe 3-X-yo4. This film is bonded to the Ni--Fe alloy layer (15) with good adhesion via the Cr enriched layer.

In addition, when the material is one in which Cr is partially replaced with tMn, the blackened film is CrxMnyNizFea-)z-y-
It has a spinel structure called zO4, and even in such a case, it exhibits the same effect. Note that when air oxidation, steam oxidation, or carbon dioxide gas oxidation is employed to form this blackened film, α-Fe203 is formed on the surface, but this does not pose a problem because the film is thin.

By the way, N is 0.006wt%, 0 is 0.005
wt'ly, 3 with 0-015 wt% of C added
6 A shadow mask made of the above material in which a blackened film having the above composition was formed on the surface of Ni-Fe and %N of 0.001% and 0.
A comparison of the PD values of each color picture tube, which was assembled using a shadow mask in which a degraded film was formed on 36Ni-Fe doped with 0.0007 wt% of C and 0.004 vt of C, revealed that C, N , 3 with few zeros
While the minute PDf directivity was 90 μm, C, N,
It was confirmed that those with many 0's had a small PD value of 75 μm.

In other words, the surface area of this blackened film is increased, the heat dissipation effect is enhanced, and a great effect is achieved in suppressing PD. Particularly, the effect of this blackened film is remarkable when a flattened 7-yado mask with a curvature of 900 mm or more is formed.

〔Effect of the invention〕

Thus, according to the present invention, C is added to a predetermined Ni-Fe alloy.
By adding r, the 0.2 inch proof stress was reduced, and by adding N, the coarsening of crystal grains was suppressed, preventing unevenness of stretching, improving the formability, and forming a black oxide film with a large surface area. Since the color picture tube is formed using tube internal parts such as a shadow mask, the image can be bright, extremely detailed, and of high 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, since the crystal grains are small and their strength is high,
It does not cause vibrations caused by low-frequency sound waves from speakers placed close to each other, and has the advantage of being able to sufficiently withstand mechanical shocks and the like, so that images without so-called fluctuations can be obtained.

[Embodiments of the invention]

Next, examples of the present invention will be described.

[Example-1] First, 36Ni and Fe are the main components, Cr is 3wt%, N is 0.005wt%, 0 is 0.004vt%, C
0.012wt%, P and S 0.05w each
Ingots of alloys each containing 1.5 t% were prepared, and the ingots were repeatedly annealed and cold-worked to produce plates with a thickness of 0.413 mm. 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 development dissolves and removes the unexposed portions of the photoresist. Thereafter, the remaining photoresist was hardened by burning, and then etched with a ferric chloride solution, and then the remaining resist was removed with a hot alkali to produce a flat mask that would serve as a shadow mask original.

After that, this flat mask was cleaned and sheared, and then vacuum annealed at 10 torr and 1000°C.
A 7-ohm mask with a radius of curvature of 10001.1 was obtained by pressing. After this foamed mask was treated with acid, washed with trichloride, and washed with water, it was heated and oxidized for 30 minutes in a 30% 02-N2 humid atmosphere at 670°C.

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.

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

[Example 2-7] Main components are 36vt%N1 and Fe, and 2 to 4w of Cr.
In some cases, the ingots containing N shown in Table 1 were used to prepare Example-1.
A flat mask was made in the same manner as above. Then, this fret mask was vacuum annealed at 1100℃ and then heated to 680℃ for 30 minutes.
A color picture tube was completed using a shadow mask that was blackened for a minute.

The margin table below also shows the grain size number shown in JIS-GO551 and the thermal emissivity of the blackened film (with a perfect black body being 1.0).

As a result of examining the PD values at the four corners of each of the color picture tubes of Examples 1 to 7 obtained in this way, the PD values were as low as about 75 degrees, whereas the conventional ones were high at about 904. showed that. In addition, the time it took to return to the original normal state after PD occurred was about 3/4 (about 2 minutes and 30 seconds) compared to conventional methods. An ultra-fine, high-quality image with only one color visible was obtained.

In addition, although the formation of a shadow mask was explained here as an example,
It is also possible to obtain a force 2-picture tube by similarly manufacturing the inner shield, frame, bimetal, etc. others,
The present invention can be implemented with various modifications such as lead frames and glass sealing materials without departing from the gist thereof.

[Brief explanation of drawings]

Figure 1 shows the schematic structure of a color picture tube. Figure 2 shows the change in 0° and 2-inch proof stress with respect to annealing temperature. Figure 3 shows the coefficient of thermal expansion and 0°2-inch proof stress as a function of the amount of Cr added. FIG. 4 is a diagram showing a cross-sectional structure of a blackened film. 1... Envelope, 3... Electron gun, 6... Shadow mask, 7... Frame, 9... Inner shield,
11...α-Fe203 layer, L2-NtzC
ryFea-z-y04 layer s13...Cra contraction layer, 1
4... Alloy grain boundary, 15--- Fe-Ni alloy. Applicant's agent Patent attorney Suzue Takehiko No. 1 Diagram: Yasutaku Onsasa (・C) Diagram 2: Disciplined by Junhari (×IO-G'c) 0.2'/J1 Shiriki<Kg/ mm2) Figure 4

Claims (2)

[Claims] (1) 25-45wt% Ni, 0.03-10wt%
Cr, 0.002 to 0.01 wt% of N, and the balance substantially of Fe. (2) The color picture tube according to claim 1, characterized in that a black oxide film is formed on the alloy surface.