JPH07272638A - Color screening mask for cathode-ray tube - Google Patents

Abstract

PURPOSE:To substantially reduce a mask oscillation phenomenon due to an external vibration such as a speaker vibration by keeping the resonance frequency of a mask within a frame non-resonance frequency via the control of the cross sectional area of a mask tape. CONSTITUTION:Regarding the color screening mask of a cathode-ray tube formed out of a frame and a slit type mask mounted on it, a mask resonance frequency is set to be within the non-resonance frequency range of the frame. In the analytical diagram of the vibration mode of the frame proper of the color screening mask, using the modal analysis method, the axis of abscissa shows a vibration applied to the frame, while the axis of ordinate shows a response amplitude corresponding to applied vibration energy. In addition, peak values (1) to (6) in the diagram correspond to the resonance frequencies of the frame. When a vibration having a frequency with the peak values (1) to (6) is applied to the frame, a vibration having a large amplitude occurs. On the other hand, hatching areas (7) and (8) show non-resonance frequency band width and when a frequency within the band with is applied, only a vibration having small amplitude appears.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color selection mask for a cathode ray tube. More specifically, the present invention is a color selection mask used for a cathode ray tube such as a trinitron type color cathode ray tube, wherein the vibration of itself is suppressed even when an external vibration from a speaker or the like is received. Regarding

[0002]

2. Description of the Related Art Generally, a color selecting mechanism such as a shadow mask is provided inside a color cathode ray tube. Although various forms of the color selecting mechanism are known, in the trinitron type color cathode ray tube, a color selecting mask 3 in which a slit-shaped mask 1 is stretched over a frame 2 as shown in FIG. 6 is usually used. Is used. The slit-shaped mask 1 of this color selection mask 3 is formed by arranging a large number of mask tapes 1a having a cross-sectional shape as shown in FIG. In addition, in FIG. 7, the arrow indicates the incident direction of the electron beam to the mask tape 1a. Further, as shown in FIG. 6, the color selection mask 3 is attached to the color cathode ray tube by fitting the spring 5 on the spring holder 4 into the glass panel of the color cathode ray tube.

However, such a color selection mask 3
When the color cathode ray tube incorporating the above is actually used in a television or the like, external vibration due to a speaker or the like propagates to the mask 1 via the spring holder 4 and the spring 5, and the mask 1 vibrates. Such vibration of the mask 1 is generally called AG shake and causes image unevenness, and therefore needs to be suppressed.

Conventionally, as a method for suppressing the AG fluctuation of the mask 1, a damper wire is provided on the emission side of the electron beam of the mask 1 or the following (1) or (2) method concerning the design of the mask itself. Is being taken.

(1) The tension distribution, which is a parameter for determining the natural frequency of the mask 1, is given a large gradient so that the central part of the screen is low and the both ends are high. That is, since the frame 2 has a window frame-like structure, the frame 2
The tension distribution of the mask 1 stretched around is inevitably shown in FIG.
As shown in FIG. 4, the tension in the central portion is low and the both ends are high, but the tension distribution of the mask 1 has a large gradient as shown in FIG. Lower, higher at both ends. As a result, in the case where the fluctuation region of a certain frequency T is the tension distribution shown in FIG. 5A, the region shown by the diagonal lines in FIG. 5B on the screen is changed from that shown in FIG. It can be a narrow area as shown by the diagonal lines. The gradient of the tension distribution of the mask 1 is
It can be controlled by the member strength of the frame 2 and the pressing method.

(2) The tension of the mask 1 is increased. When the tension of the mask 1 is increased, the amplitude of the mask 1 with respect to the same vibration energy from the outside can be reduced as compared with the case where the tension is low. Therefore, the AG shake can be made inconspicuous.

[0007]

However, the method (1) for providing the mask 1 with a large tension distribution is as follows.
Specifically, since it is performed by lowering the tension of the central portion of the mask 1, there is a problem that when external vibration having a resonance frequency of the central portion propagates, a large AG swing occurs in the central portion. In addition, external vibration due to a speaker or the like generally has a plurality of frequency bands rather than a single frequency, so that there is a problem that AG vibration occurs simultaneously at a plurality of locations on the mask 1.

On the other hand, in the above method (2), the frame 2
Since it is necessary to make the frame strong, the frame 2 becomes heavy and the cost becomes high.

The present invention is intended to solve the problems of the prior art as described above, and it is an object of the present invention to greatly reduce the mask sway phenomenon (AG sway) due to external vibration of a speaker or the like.

[0010]

Means for Solving the Problems As a result of various studies conducted by the inventor in order to achieve the above object of AG swing,
In a color selection mask in which a slit-shaped mask is stretched over a frame, the vibration transfer function of the entire color selection mask is a combination of the transfer function of the vibration peculiar to the frame and the transfer function of the vibration of the mask tape. That is, conventionally, as a method for reducing the AG shake, attention has been paid exclusively to controlling the tension distribution of the mask, and the transfer function of each vibration of the frame and the mask has not been considered, As a result, the resonance frequency of the frame and the resonance frequency of the mask overlapped with each other, but in order to reduce the AG fluctuation, it is effective to set the resonance frequency of the mask within the non-resonant wave number range of the frame. Then, it has been found that controlling the cross-sectional area of the mask tape constituting the mask is effective for that purpose, and has completed the present invention.

That is, according to the present invention, in a color selection mask for a cathode ray tube comprising a frame and a slit-shaped mask stretched over the frame, the resonance frequency of the mask is in the non-resonance frequency range of the frame. Provide a color selection mask that does.

[0012]

The vibration transfer function as a whole of the color selection mask in which the slit-shaped mask is stretched over the frame is obtained by superposing the transfer function of the vibration peculiar to the frame and the transfer function of the mask tape constituting the mask. However, in the color selection mask of the present invention, the resonance frequency of the mask falls within the non-resonance frequency range of the frame, and the resonance frequencies of both do not overlap. Therefore, it is possible to greatly reduce the amplitude of the mask when the external vibration propagates to the color selection mask, as compared with the case where the resonance frequencies of the both overlap.

[0013]

EXAMPLES The present invention will be specifically described below based on examples.

FIG. 3 is an analysis diagram of a vibration mode of a single frame of a color selection mask used in a general trinitron type color cathode ray tube by a modal analysis method, where the horizontal axis represents the frequency applied to the frame and the vertical axis. The axis is the response amplitude for the given vibration energy. In the figure, the peaks (1) to (6) are the resonant frequencies of the frame. Therefore, if vibrations with frequencies of peaks (1) to (6) are applied to this frame, large amplitude fluctuations will occur. On the other hand, in the figure, the shaded areas (7) and (8) are non-resonant frequency bands, and when a frequency in this band is applied, only small amplitude fluctuations occur. Therefore,
In the present invention, the resonance frequency of the mask stretched over the frame is in the non-resonance band frequency range of the frame (the shaded area (7) in FIG. 3).
(8)) Design the mask so that it enters.

That is, the resonance frequency f of the mask is expressed as follows:

[0016]

[Equation 1] Is expressed as From this equation, it is possible to control the resonance frequency f by changing the cross-sectional area s of the mask tape, and more specifically, the resonance frequency f can be set high by decreasing the cross-sectional area s of the mask tape, and the cross-sectional area s It can be seen that the resonance frequency f can be set low by increasing the value. In addition, the resonance frequency f depends on the length l of the mask tape,
It can be understood that the control can be performed even if the load (tension) t and the density ρ _{Fe of the} constituent material are changed, but it is not easy to obtain the predetermined resonance frequency f by changing the design when manufacturing the mask. Therefore, when controlling the resonance frequency f, it is preferable to change the cross-sectional area s of the mask tape.

Therefore, in the present invention, it is preferable to first determine the non-resonance band of the vibration mode of the frame by the modal analysis method and determine the cross-sectional area s of the mask tape so that the resonance frequency f of the mask falls within the frequency range. It is preferable to determine the sectional shape of the mask tape so as to have such a sectional area s.

For example, when the mask is produced by etching, an etching pattern and etching conditions (etching solution composition, temperature, viscosity, etc.) are appropriately selected, and the sectional shape of the conventional mask tape 1a shown in FIG. The groove x is formed on the surface like the etching tape 1b shown in FIG. 1, or the length and depth of the tapered portion y are changed like the etching tape 1c shown in FIG.

By thus controlling the cross-sectional shape of the mask tape so that the resonance frequency of the mask falls within the non-resonance frequency range of the frame, for example, the resonance frequency of the mask overlaps the frequency of the peak (3). Compared with the case, the amplitude of the mask can be reduced to about 1/100 or less. Further, as shown in FIG. 2, if the taper portion y is formed to be long and deep and the taper width z on the electron beam emission side is made small, the contact area between the damper wire and the mask attached for the purpose of damping the AG fluctuation is small. Therefore, it is possible to prevent the phenomenon that the mask tape is caught with the damper wire,
It is also possible to suppress pitch moire and damp parlra without changing the damping characteristics.

The color selection mask of the present invention can be constructed in the same manner as the conventional color selection mask except that the resonance frequency of the mask is set as described above. For example, the frame and the constituent material of the mask are conventional. The same can be used.

[0021]

According to the present invention, it is possible to greatly reduce the shaking phenomenon of the mask due to the external vibration of the speaker or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mask tape of the present invention.

FIG. 2 is a cross-sectional view of the mask tape of the present invention.

FIG. 3 is an analysis diagram of a vibration mode of a frame.

FIG. 4 is a tension distribution diagram (a) of a mask in which a tension distribution has a large gradient in order to reduce AG swing, and a diagram (b) showing a swing region on a screen.

5A is a tension distribution diagram of a general mask and FIG. 5B is a diagram showing a shake region on a screen.

FIG. 6 is a perspective view of a general color selection mask.

FIG. 7 is a cross-sectional view of a conventional mask tape.

[Explanation of symbols]

 1 mask 1a, 1b, 1c mask tape 2 frame 3 color selection mask

Front page continued (72) Inventor Kazuaki Yazawa 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (4)

[Claims] 1. A color selection mask for a cathode ray tube comprising a frame and a slit-shaped mask stretched over the frame, wherein the resonance frequency of the mask falls within a non-resonance frequency range of the frame. . 2. The color selection mask according to claim 1, wherein the cross-sectional area of the mask tape constituting the mask is controlled so that the resonance frequency of the mask falls within the non-resonance frequency range of the frame. 3. A groove is formed on the surface of the mask tape to control the cross-sectional area of the mask tape.
The color selection mask described. 4. The color selection mask according to claim 2, wherein a large taper is formed on an emission side surface of the mask tape for emitting an electron beam in order to control a cross-sectional area of the mask tape.