JPH0320009B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fluorescent display tube, and more particularly to a mounting structure for a grid for controlling electrons emitted from a filament.

[Prior art]

An example of the grid mounting structure conventionally used in fluorescent display tubes will be explained with reference to FIGS. 1 and 2. FIG. 1 shows a schematic cross-sectional view of a conventional fluorescent display tube, and FIG. shows a plan view of the grid section. In these figures, reference numeral 1 denotes a substrate made of glass or the like, and on the surface of the substrate 1, segment electrodes 2 in the shape of Japanese characters, for example, are arranged according to the number of digits. A phosphor layer 3 is applied forming the display pattern. Further, the segment electrodes 2 constituting this display pattern are connected to a wiring layer 4 formed in a predetermined pattern on the substrate 1, and are electrically connected to lead terminals 6 through the lead-out conductive layer 5. It is connected. Further, mesh-shaped grids 8 are arranged between the display patterns and the filament 7 so as to cover each display pattern. In this case, each of the grids 8 is formed by bending both ends of an ultra-thin stainless steel plate on which a mesh has been formed by etching into an inverted L shape so as to maintain a constant gap with the display pattern, and fixing the ends. Legs 9a and 9b are arranged on the substrate 1. Then, frit glass 11 is applied to one of the fixed leg parts 9a, and conductive paste 12 is applied to the other fixed leg part 9b, and by drying and baking, the display pattern and the filament 7 are coated.
Each gap is secured and fixed. Also,
Each grid 8 is also electrically connected to a lead terminal 6 via a lead-out conductive layer 5, similarly to each segment electrode 2. Each electrode assembly constructed in this manner is hermetically sealed in an airtight container comprised of a substrate 1 and a face glass 14 sealed with a low melting point glass 13 thereon to constitute a fluorescent display tube. are doing. Note that 15 is an insulating layer applied over almost the entire surface of the wiring layer 4 on the substrate 1 except for the lead-out conductive layer 5, and 16 is a solder for electrically connecting each lead-out conductive layer 5 and the lead terminal 6. , 17 is a resin for reinforcing the lead terminal 6.

However, in such a conventional grid mounting structure, since the fixed legs 9a and 9b of each grid 8 are fixed with frit glass 11 and conductive paste 12, each grid 8
When the dimension of the grid in the vertical direction Y increases, there is a problem that the grid tends to sag due to its own weight.

In order to eliminate this drawback, as shown in FIG. 3, a mesh-shaped grid 8 is welded and fixed onto a metal spacer 20, and the fixing legs 9a ₁ and 9b ₁ at both ends are fixed as in the conventional case. There is also one in which the glass is fixed with a frit glass 11 and a conductive space 12, respectively. Note that a part of the metal spacer 20 may be directly drawn out of the airtight container and configured as an external terminal.

However, even with such a grid mounting structure, if the vertical dimension of the grid 8 becomes large or if the driving conditions (high driving voltage) are changed to obtain high brightness, the grid will generate heat due to the grid current during driving. This causes problems such as deformation of the grid, causing changes in the light emitting state, that is, uneven brightness, and deterioration of display quality. Also,
In the worst case, if the grid is deformed, it may come into contact with the display pattern or the filament, leading to damage to the fluorescent display tube.

[Summary of the invention]

In view of the above points, the present invention has been made in order to eliminate such drawbacks of the conventional art. By configuring so that the rising portion of each fixing leg portion, including the frit glass coating portion on the grid side, is embedded in the frit glass over the entire surface thereof and is fixed to the substrate by the frit glass,
To provide a fluorescent display tube which can be mounted with tension applied to the grid and which can prevent deformation of the grid due to heat generation during operation. Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

4 and 5 are a main cross-sectional view and a plan view of the grid portion of an embodiment of the fluorescent display tube according to the present invention, and in these figures, the first
The same or corresponding parts as in the figures and FIG. 2 are given the same reference numerals. In this embodiment, both ends of a mesh-like grid 8 are shaped into an inverted L shape to form fixed leg parts 9a and 9b, and these grids 8 are arranged corresponding to the display pattern on the substrate 1, respectively. The fixed legs 9a and 9b of each grid 8 are the same as the conventional one shown in FIG.
are placed on the substrate 1, and the rising portions 10a and 10b of the fixed legs 9a and 9b are embedded in frit glasses 11a and 11b, respectively, and fixed, and one of the fixed legs 9 is
b is fixed with conductive paste 12 for conductive connection. The frit glasses 11a and 11b are applied onto the substrate 1 through the frit glass application parts A and B provided inside the rising portions 10a and 10b of the fixed legs 9a and 9b of the grid 8, and then dried and fired. By doing this, grid 8 is created as shown in Figure 4.
It can be fixed using the rising portions 10a and 10b on both sides.

Thus, in the present invention, the rising portions 10a, 10b of each fixed leg 9a and 9b of the grid 8
By fixing them with frit glasses 11a and 11b, respectively, the frit glasses 11a and 11
b and the thermal expansion of the grid 8 that occurs during firing of the conductive paste 12 and the respective frit glasses 11a,
The grid 8 can be fixed with tension by utilizing the sintering of the conductive paste 11b and the conductive paste 12, that is, the difference in thermal expansion (coefficient). In detail, when the frit glass 11a, 11b and the conductive paste 12 are applied and the grid 8 is fixed on the substrate 1, and the temperature is increased for sintering, the grid (metal) 8 is bonded to the substrate (glass) 1. Since the amount of expansion is larger than that of the actual product, it is fixed in a fully expanded state.
Next, when the sintering is finished and the temperature is returned to room temperature, the grid 8 continues to be under tension because it shrinks more than the substrate 1. Therefore, since the grid 8 is stretched uniformly, the gaps between the grid 8, the display pattern, and the filament are uniform, eliminating uneven brightness and improving display quality. Since the frit glass is applied through the frit glass application parts A and B, which are formed in the shape of a larger window frame than the usual mesh part, the frit glass can be reliably applied onto the substrate. Therefore, it is possible to prevent the amount of coating due to variations in the coating operation, the resulting deformation of the grid after firing the frit glass, and the peeling of the frit glass. Further, when the fixed legs 9a and 9b of the grid 8 are fixed as in the above-mentioned conventional method, the rising portion (the first
(see figure) is free, so grid 8
However, according to the present invention, since the rising portions 10a and 10b of the grid 8 are fixed, deformation of the grid can be suppressed, and deformation due to heat generation during operation can be prevented. Furthermore, since no metal spacer is required, there are advantages such as cost reduction.

Note that the present invention is not limited to the above-described embodiment, but as shown in FIG.
It is also possible to fix the rising portions of the fixed legs 9a and 9b with fritted glass (not shown), and to fix two parts of one fixed leg 9b with conductive paste 12.

〔Effect of the invention〕

As explained above, the present invention provides a fluorescent display tube in which grids are arranged corresponding to display patterns formed on a substrate, each having an inverted L-shape so as to maintain a predetermined gap with the display pattern. The rising portions of the fixing legs provided at both ends of each grid shaped as shown in FIG. With this configuration, it is possible to attach the grid by applying tension to the grid, and it is also possible to prevent deformation of the grid due to heat generated during operation. In particular, not only the rising part of the fixed leg,
In order to apply the frit glass over the entire surface including the inner frit glass application areas A and B,
The frit glass can be reliably applied onto the substrate, and it is possible to prevent variations in the amount of coating due to variations in coating work, deformation of the grid after firing the frit glass, and peeling of the frit glass.
Moreover, it has the effect of improving display quality and reducing costs.

[Brief explanation of the drawing]

1 and 2 are a schematic cross-sectional view and a plan view of a grid portion of a conventional fluorescent display tube, and FIG.
4 and 5 are main sectional views and a plan view of the grid portion showing one embodiment of the present invention.
This figure is a plan view of a grid portion showing a modification of FIG. 5. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Segment electrode, 3... Fluorescent layer, 4... Wiring layer, 5... Leading conductive layer, 6... Lead terminal, 7... Filament, 8... Grid, 9a, 9
b...Fixed leg portion, 10a, 10b...Rising portion, 1
1a, 11b... Fritted glass, 12... Conductive paste.

Claims (1)

[Claims] 1. In a fluorescent display tube in which grids are arranged corresponding to display patterns formed on a substrate, each grid is shaped into an inverted L shape so as to maintain a predetermined gap with the display pattern. The rising portions of the fixing legs provided at both ends of the board are fixed to the substrate by the frit glass in such a manner that they are embedded in the frit glass over the entire surface thereof, including the frit glass coated part on the grid side. fluorescent display tube.