JP2902004B2 - Shadow mask and method of manufacturing the same - Google Patents

Description

The present invention relates to a shadow mask used for a color picture tube or the like, and a method of manufacturing the same.

(Prior Art) In recent years, color televisions and the like have been increasingly refined in addition to their large size, and users are becoming more and more upscale.

For example, large screens such as 25-inch to 40-inch screens are required and put into practical use. In these screens, finer and higher-quality screens, that is, high-resolution product development are required. Along with this demand, the color picture tube will also have a mission to have a high resolution, of course, and will depend entirely on this characteristic.

In order to maintain and improve this characteristic, the quality of the shadow mask, which is essential for controlling the passage of the electron beam, has a large direct effect on the quality of the screen. Therefore, the quality of the shadow mask is important and is a key point that affects the image quality.

In order for the shadow mask, which is the key point, to sufficiently meet the above requirements, a large number of electron beam passage holes in the shadow mask body (hereinafter, referred to as the mask body) must be formed, and the effective beam passing through the passage hole must be formed. In addition, it is necessary to eliminate the obstructive elements described above and to maintain the relative positional relationship of the mask body with respect to the phosphor screen at a predetermined position during operation.

In such elements of (1), (2) has been solved quite technically. The use of an invar alloy having a low coefficient of thermal expansion as a material for the shadow mask has also been greatly improved.

However, the following problems have emerged.

That is, when the thickness of the mask body is reduced to 0.15 mm to improve the above, the mechanical strength is reduced as compared with the conventional one. When this reduction occurs, the effective surface of the mask body through which the electron beam passes can be shifted even by a slight external vibration. This phenomenon will be described with reference to FIGS.

The shadow mask 1 in FIG. 3 includes a mask frame 2, a mask body 3, and a mask support 4, and is fixed to the side wall of the face portion 5 via the mask support 4. When a certain kind of impact is applied to the color picture tube in the mask body 3 fixed as described above, the vibration path is changed to the mask support 4-the mask frame 2-the skirt portion of the mask body 3.
3a-to sequentially transmit to the effective surface 3b of the mask body 3. And
This vibration vibrates back and forth (A and B) with respect to the phosphor screen 6. This vibration greatly affects the image quality, and appears as a color shift phenomenon of the image.

That is, if the vibration mask body 3 in a normal state, as shown in FIG. 4, the electron beam E ₁ is to impinge on the predetermined phosphor screen 6 by normal electron beam scanning, vivid color shift Will be displayed without the screen, but the mask body 3
When the effective surface of is shaken forward by A as shown by the broken line A,
Electron beam passes through the passage hole crazy mask body 3 becomes E _2, in this way the passage of the electron beam is out of order, the electron beam impinges at an undesired form the phosphor of the phosphor screen 6 Therefore, a color shift occurs. Such a phenomenon is a so-called howling phenomenon, which is a factor that significantly lowers image quality.

Most of the vibration is eliminated by removing a frequency band of about 20 to 250 Hz which is particularly easy for the human eye to perceive, but conventionally, the vibration was affected by this frequency band.

(Problems to be Solved by the Invention) As described above, the conventional shadow mask is affected by externally applied vibration such as sound volume, thereby causing a color shift on the screen.

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems, and to provide a shadow mask capable of improving the vibration damping ability (hereinafter simply referred to as damping ability) of a shadow mask and preventing color shift, and a method of manufacturing the shadow mask. It is in.

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present inventors have conducted intensive studies, and have appropriately selected the types of components and adjusted the amounts of the components. The present inventors have found that a remarkable effect can be obtained by performing a solution treatment by annealing the mold alloy after press forming, and have completed the present invention.

That is, in the shadow mask according to the present invention, niobium (Nb), tantalum (T
a) At least one kind of titanium (Ti) is dissolved in a solid solution of 0.1 to 5% by weight, and the attenuation capability at 200 Hz is 1.5 × 10 ⁻³ or more. The practical Vickers hardness is preferably 2 × 10 ⁻³ or more, more preferably 3 × 10 ⁻³ or more.

The reason why the damping power is set to 1.5 × 10 ⁻³ or more is that the damping power is 1.5 × 10 ⁻³ or more.
This is because a howling phenomenon is likely to occur when the ratio is × 10 ⁻³ or less.

The shadow mask according to the present invention includes a mask body, a mask frame, and a mask support.

Further, as the amber alloy according to the present invention, 30 to
45% by weight of nickel (Ni) and the balance substantially iron (Fe)
Alloy (amber alloy) or 30-45% by weight of Ni, 0
An alloy (super-amber alloy) of about 10% by weight of cobalt (Co) and the balance substantially composed of Fe is used.

In the material of the shadow mask of the present invention, Nb, T
The content of a and Ti in an amber-type alloy is not improved unless at least one of these elements is contained in an amount of 0.1% by weight or more. It is not preferable because the coefficient is increased.

Further, in the method for manufacturing a shadow mask according to the present invention, after the step of press-molding an amber-type alloy material containing 0.1 to 5% by weight of at least one of Nb, Ta, and Ti, the temperature exceeds 800 ° C. It is characterized by comprising a step of annealing at a temperature. The annealing performed after the step of press molding is more preferably performed at a temperature exceeding 800 ° C. and 1200 ° C. or less.

The reason for setting the annealing temperature to a temperature exceeding 800 ° C is that the annealing temperature is 800 ° C.
If the content is below, the substance contained in the amber-type alloy is not dissolved in the amber-type alloy, and the Vickers hardness does not decrease, that is, the damping ability is not improved. Also,
The reason why the temperature is preferably 1200 ° C. or less is that even when annealing at or above this temperature is performed, no improvement in damping ability is observed.

(Function) When the object is vibrated, the vibration always stops because the energy of the vibration is transmitted through the air or the support to escape. However, even in a vacuum, the internal friction of an object
Because of this, the energy of vibration is converted into heat inside the object and is consumed.

Although the causes of the wear are various, the vibration amplitude of the body with the wear decreases exponentially with time. Considering the origin of a certain vibration, the n-th vibration amplitude is A _n , and the first amplitude is A ₀ , Holds. That is, since the way in which the amplitude decreases is determined by the magnitude of Δ, Δ is a measure of the degree of decrease in amplitude. This Δ is called a logarithmic decay rate, and it can be said that the larger this value is, the larger the damping ability is. In a normal wear device,
Instead of the logarithmic decay rate Δ, a damping capacity Q ⁻¹ (reciprocalQ) is measured, and the following relationship exists between the damping capacity Q ⁻¹ and Δ.

It is known that when such an attenuation power Q ^-1 is 10 ^-3 or more, the howling phenomenon hardly occurs in the shadow mask. And this damping capacity Q- ¹ shows a relatively high value in the amber-type alloy that has been annealed according to the solution treatment before press forming, but when press forming is performed,
It decreases to about half. That is, it is considered that the slip band due to the dislocation generated inside the amber-type alloy after the press forming resonates with the vibration and prevents the damping of the vibration, so that when the press forming is performed, the damping ability Q- ¹ decreases. . For this reason, it is considered that the damping ability Q- ¹ is improved by removing the crystal defects by annealing (solution treatment) with high heat after press molding.

The present inventors have found that the shadow mask according to the present invention has low hardness when the attenuation power Q- ¹ is large. That is, Ti, Nb,
The Ta or the like, in each material containing a solid solution, respectively in weight percent shown in Table 1, when examining the relationship between the damping capacity Q ^-1 and Vickers hardness, as shown in FIG. 1, damping capacity Q ^{- 1} is 1
At ~ 2 × 10 ^-3 , the Vickers hardness was 240 or less (500 g load). According to the relationship shown in FIG. 1, the Vickers hardness could be used as a measure of the progress of solution treatment, that is, improvement of damping ability.

(Example) Example 1 A material made of an Invar alloy (Ni 39% by weight, balance Fe) containing 1.0% by weight of Nb was used.
A mask main body thick plate having a thickness of 15 mm was prepared, various processes were performed on the original plate, electron beam passage holes were provided by photoetching, and press forming was performed after annealing. Next, annealing was performed to about 1100 ° C. FIG. 2 shows the change in Vickers hardness with the annealing temperature, and the damping capacity Q obtained based on the relationship between the Vickers hardness and the damping capacity Q- ¹ shown in FIG.
^-1 is shown in Table 1.

Examples 2 to 8, Comparative Example 1 A shadow mask was manufactured in the same manner as in Example 1 except that the components of the amber alloy were variously changed as shown in Table 1, and then press-molded in the same manner as in Example 1. A subsequent annealing was performed, and the results are also shown in Table 1 and FIG.

As is evident from Table 1, the damping capacity Q ^-1 of the invar alloy containing no Nb, Ta, or Ti (Comparative Example 1) is as follows.
0.7 to 1.0 × 10 ^-3 when no annealing after press forming, and 1.1 to 1.4 × 10 ^-3 be annealed after press forming, a large change is not,
If an invar alloy containing 0.1 to 5% by weight of at least one of Nb, Ta and Ti is subjected to annealing and solution treatment after press forming, the result is that the damping ability Q- ¹ is improved by about 2 to 4 times. Obtained. When annealing at a temperature of 800 ° C or more to reduce the Vickers hardness (500g load) to 190 or less, the damping capacity Q
^-1 improved further.

[Effects of the Invention] As is clear from the above description, in the shadow mask and the method of manufacturing the same according to the present invention, the shadow mask and the amber-type alloy containing at least one of Nb, Ta, and Ti in an amount of 0.1 to 5% by weight. After press forming, by performing a solution treatment by annealing, the damping capacity can be increased, so the wall thickness is 0.15 mm
Even thin shadow masks can efficiently attenuate vibrations applied from the outside to prevent color shift on the screen due to the vibrations, and their industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between Vickers hardness and damping ability obtained in the shadow mask according to the present invention.
FIG. 3 is a graph showing the relationship between the annealing temperature and Vickers hardness obtained in the shadow mask shown in FIG. 1, and FIGS. 3 and 4 are the main parts of a color picture tube to which the shadow mask according to the present invention is applied. It is sectional drawing. 1 shadow mask 2 mask frame 3 mask body 4 mask support

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Morio Fumio 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Yokohama Office (56) References JP-A-61-177359 (JP, A) JP-A-63 -72026 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 29/07 H01J 9/14 C22C 38/00 302 C22C 38/14

Claims (4)

(57) [Claims] 1. A shadow mask, characterized in that at least one of niobium, tantalum and titanium is fixed at 0.1 to 5% by weight in an amber alloy. 2. The shadow mask according to claim 1, wherein the vibration damping ability at 200 Hz is 10 ^-3 or more. 3. At least one of niobium, tantalum and titanium.
A method for producing a shadow mask, comprising a step of performing an annealing process as a soaking process after a step of press-forming a material of an amber type alloy containing 0.1 to 5% by weight of a seed. 4. The method of manufacturing a shadow mask according to claim 3, wherein the annealing temperature is higher than 800 ° C.