JPH0570253B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a container for a flat vacuum display tube.

Conventional Structures and Problems Glass has conventionally been used as the material for containers such as fluorescent display tubes and flat television picture tubes. This is mainly due to the following reasons.

(1) Since the display area is the inner surface of the glass container, high transparency is required.

(2) In order to control the electron beam, it is necessary to maintain a vacuum inside the container. Therefore, a material with good sealing properties is required.

(3) In order to completely seal the container after inserting the contents such as electrodes into the container, the container must be heated and sealed to, for example, 400°C. The entire material is required to be made of a uniform material with the same coefficient of thermal expansion.
However, as the display tube becomes larger, the wall thickness of the glass container becomes thicker in terms of its vacuum resistance, resulting in an increase in weight, which is a serious drawback that prevents commercialization.

Therefore, the present inventors have already proposed a configuration in which a honeycomb structure plate as shown in FIG. 2 is applied as the back panel of a flat vacuum display tube whose appearance is shown in FIG. 1. In Figure 1, 1
1 is a display panel, 2 is a rear panel, and FIG. 1b is a view seen from the direction of arrow A in FIG. 1a.
In addition, in Fig. 2, 3 is a honeycomb flat plate, 4,
5 is a glass flat plate. As shown in FIG. 2, the thickness of the honeycomb flat plate 3 is h, and the thickness of the glass flat plates 4 and 5 is 1
Let the thickness per sheet be t.

Previous proposals by the present inventors had only shown an example of the structure of a container using a glass plate with a honeycomb structure, so it was necessary to carry out further studies in terms of optimal strength design. Ta.

Purpose of the Invention In view of the above-mentioned problems, the present invention determines the optimal shape in terms of strength and weight of a vacuum display tube container made only of glass, based on the results of structural analysis using the finite element method. The purpose of the present invention is to provide a vacuum display tube container that achieves weight reduction while maintaining sufficient vacuum resistance without using materials other than glass.

Structure of the Invention The present invention consists of a display panel made of glass and a rectangular back panel made by sandwiching and bonding both sides of a glass honeycomb flat plate having holes with a regular hexagonal cross section between two glass flat plates. The length of the short side of the back panel is a, the thickness of one of the two glass plates is t, the thickness of the honeycomb flat plate is h, the pitch of the holes with the regular hexagonal cross section is p, and the distance between the holes is Letting the wall thickness be δ, the dimensionless quantity obtained by dividing p by a, the dimensionless quantity obtained by dividing h by p, the dimensionless quantity obtained by dividing t by h,
If we define the dimensionless quantity obtained by dividing δ by h, then
0<≦0.2, 0.55≦≦0.65, 0.1≦, respectively.
Value limited to δ≦0.3. The present invention provides a vacuum display tube container that maintains sufficient vacuum resistance and is lightweight without using any material other than glass.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The embodiment of the present invention has the same shape and configuration as the one already proposed by the inventors, whose perspective view is shown in FIG. We aim to optimize the equation, set various dimensionless quantities, and give numerical limitations.

Next, we will outline the progress of the structural analysis.

First, as a first step, we compared the bending rigidity when the weight of the honeycomb flat plate was kept constant, that is, when the pitch between the holes and the cross-sectional area of the holes were made equal and the cross-sectional shape of the holes was changed. Calculations were performed only for the back panel with the configuration shown in Figure 2, with simple support around the periphery, the thickness of the two glass plates t = 2 mm, the thickness of the honeycomb flat plate h = 10 mm, and the length of the short side of the back panel. a=
230 mm, the length of the long side b = 280 mm, and the pore shapes of the honeycomb are three types shown in Fig. 3: a circular cross section shown in Fig. 3 a, a rectangular cross section shown in Fig. 3 b, and a pore shape of the honeycomb as shown in Fig. 3 b.
A comparison was made regarding the regular hexagonal cross section shown in Figure c. In addition, the pitch p in Fig. 3 is constant at 17 mm,
In order to make the pore cross-sectional area less obvious, δ ₁ = 2 mm, δ ₂ =
2.52, and δ ₃ =2.71. As a result of calculation, the difference between the hole cross-sectional shapes in the maximum displacement and maximum bending stress at the center of the plate was about 1 to 2%, so if the hole cross-sectional area is constant, the hole cross-sectional shapes are similar. It is judged that there is almost no significant difference in bending stiffness due to the difference.
We decided to proceed with the calculations for the next step by applying a regular hexagonal cross section that allows the wall thickness between adjacent holes to be relatively large.

Next, a method for determining the optimal values for the thickness h of the honeycomb flat plate and the thickness t of the glass plate will be described.

First, according to another calculation that we previously conducted, the bending stiffness of the honeycomb flat plate alone contributes only about 10% to the bending stiffness of the entire back panel.
Rather, it can be considered that the purpose is to ensure the offset of the glass flat plate from the neutral axis of the back panel. Therefore, by comparing the bending stiffness of two offset glass plates, we can roughly determine h and t.
The optimal value of can be found.

Furthermore, according to the results of structural analysis of conventional asymmetric vacuum display tube containers, in order to keep the maximum stress below the allowable stress of the glass, the section modulus Z per unit width of the back panel must be 40 mm ³ or more. It is known. Therefore, when Z=40 mm ³ (constant) and the weight of the back panel is minimized when h and t are changed, the optimum values of h and t are given.

FIG. 5 shows the change in the total weight of the back panel when the honeycomb plate thickness is changed when the section modulus Z is 40 mm ³ (constant). However, the cross-sectional area of the pores in the honeycomb flat plate at this time is determined by first comparing the pore cross-sectional shapes, that is, p = 17 mm, δ ₃ = 2.71
Matched to mm. From the graph in Figure 5, h is 10mm
The weight of the back panel is minimized in the front and rear. From this graph, the honeycomb plate thickness h is determined by the hole pitch p.
It can be seen that the dimensionless quantity divided by can be set to 0.55≦≦0.65.

Next, we calculated the maximum stress and displacement of the back panel when the pitch p between holes was fixed at 17 mm and the minimum wall thickness δ between adjacent holes was changed. It became as shown in Figure 6. However, in the calculation model, the entire circumference of the back panel is simply supported, and one
The horizontal axis of the graph shown in Figure 6 is a dimensionless quantity obtained by dividing the minimum wall thickness δ between adjacent holes by the thickness h of the honeycomb flat plate.
The vertical axis shows the dimensionless quantity σ _nax , which is the maximum stress divided by δ ₃ = p, that is, the maximum stress when there are no holes in the honeycomb plate, and the maximum displacement, which is also the maximum displacement when δ ₃ = p. The dimensionless quantity _nax divided by is calculated.
The reason why the values of _nax and _nax in FIG. 6 are indicated by diagonal lines is to represent the range of calculated values when changing the value from 0.55 to 0.65.

From the graph in Figure 6, if is less than 0.1,
It can be seen that both σ _nax and _nax increase rapidly, and when σ exceeds 0.3, they hardly decrease.
Therefore, from this result, it is sufficient to set 0.1 to 0.3.

The above calculation was performed for a 10-inch vacuum display tube, but since three-dimensionally similar shapes can be considered to have the same strength, the numerical limitation of the dimensionless quantity mentioned above is based on the display screen. This holds true regardless of the size of.

In addition, when the same evaluation was performed when the inter-hole pitch p was changed under the condition that the cross-sectional area of the holes was constant (that is, the weight was constant), (=P/a) was found to be
Since there was almost no significant difference in the calculation between 0.05 and 0.2, the limit was set to 0.2 or less.

Effects of the Invention As described above, the present invention applies a honeycomb structured flat plate having holes with a regular hexagonal cross section to the back panel of a vacuum display tube container whose front and back are asymmetric.
A glass vacuum display tube with a display surface of any size can be created by adding numerical limitations based on structural analysis results using the finite element method to dimensionless quantities obtained by making the honeycomb shape etc. dimensionless. This provides an optimal shape for the back panel of the present invention, and it is possible to realize weight reduction while maintaining sufficient vacuum resistance without using materials other than glass such as metal.

[Brief explanation of the drawing]

Figure 1a is a perspective view showing the appearance of a conventional vacuum display tube case with front and back asymmetrical, and Figure 1b is an arrow A in Figure 1a.
2 is a perspective view showing the back panel of an embodiment of the present invention, FIG. 3a is a plan view of a honeycomb with circular holes, and FIG. 3b is a plan view of a honeycomb with rectangular holes. Figure 3c is a plan view of a honeycomb with regular hexagonal holes, Figure 4a is a side view of the honeycomb structured back panel, Figure 4b is a diagram showing the section modulus of the honeycomb structured back panel, and Figure 5 is the back side. FIG. 6 is a diagram showing the changes in the total weight of the panel, and is a diagram showing the changes in the maximum stress and maximum displacement of the back panel in a dimensionless manner. 1...Display panel, 2...Back panel, 3...
...Honeycomb flat plate, 4,5...Glass flat plate.

Claims (1)

[Claims] 1 Consisting of a display panel made of glass and a rectangular back panel made by sandwiching and bonding both sides of a glass honeycomb flat plate having holes with a regular hexagonal cross section between two glass flat plates, the short side length of the back panel is The length is a, the thickness of one of the two glass plates is t, the thickness of the honeycomb flat plate is h, the pitch of the holes with the regular hexagonal cross section is p, the wall thickness between the holes is δ, p to a
If we define the dimensionless quantity obtained by dividing h by p, the dimensionless quantity obtained by dividing t by h, and the dimensionless quantity obtained by dividing δ by h, then each of them is 0< Flat vacuum display tube container with ≦0.2, 0.55≦≦0.65, 0.1≦≦0.3.