JPS61203555A - Fluorescent light source tube - Google Patents

Abstract

PURPOSE:To improve the reliability of a fluorescent light source tube by installing a few insulating layers, having slit-like openings for exposing the phosphors of a phosphor dot array located on an anode, on the anode and installing a grid electrode over the insulating layers. CONSTITUTION:Several phosphors 3 are placed on an anode 2a on a base plate 1 along its longitudinal direction to form a phosphor dot array. Next, insulating layers 7 and 8 having slit-like openings for exposing the phosphors 3 are installed on the anode 2a and then a grid electrode 5 is placed over the insulating layers 7 and 8, thereby constituting a fluorescent light source tube. The insulating layer 7 is formed by exposing noncrystalline glass to light and the insulating layer 8 is formed by subjecting noncrystalline glass to screen printing. The width of the slits 13 is adjusted to be larger than that of slits 12. Due to the above structure, the number of pin holes is reduced, the positional accuracy is increased and any contact between a grid 5 and the anode 2a is prevented. Consequently, it is possible to improve the yield and the reliability of the fluorescent light source tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluorescent light source tube used in facsimile light sources, copying machine light sources, and the like.

[Conventional technology]

In a fluorescent light source tube, a light emitting point is formed by a phosphor coated on an anode formed on an insulating substrate, and a plurality of light emitting points are arranged side by side in one direction to form a light emitting point array. By selecting any one of the anode leads drawn out of the vacuum container on the insulating substrate, the phosphor on the selected anode is made to emit light by cathodoluminescence. It is used as a light source for facsimile machines and copying machines.

FIG. 3 is a plan view showing the substrate structure of a conventional fluorescent light source tube. In the figure, 1 is an insulating substrate, 2 is the details of the 4th
As shown in the figure, one end 2a is arranged in a straight line as an anode, and the other end 2b is alternately pulled out of the vacuum container as an external IJ-do. It is the lead. Further, 3 is a phosphor made of, for example, znO:zn, which is coated on one end 2a (hereinafter referred to as anode) of each anode/external lead 2 to form a light emitting point, as the details are shown in FIG. These phosphors 3 are arranged in a row along the longitudinal direction of the insulating substrate 1 to form a row of light emitting points. 4 is a phosphor 3 on the insulating substrate 1;
5 is an insulating layer having slit-like openings 10 formed to expose the phosphors 3 along the arrangement direction of the insulating layer 4; The electrode 6 is a cathode stretched over the grid electrode 5. Note that the insulating substrate 1 is sealed with a face glass (not shown) to form a vacuum container. Further, the symbol d in FIG. 5 indicates the opening 11 of the grid tff15.
It shows the width.

By the way, the fluorescent light source tube configured as described above has 10.
Since a high brightness of around 100 mAA-In is required, the current incident on the phosphor layer needs to have a high current density of around 100 mAA-In. In order to obtain such a high current density, the distance between the cathode 6 and the phosphor 3 is very narrow, 0.5 to 1 m, and the grid electrode 5 is placed directly on the insulating layer 4.

Therefore, the insulating layer 4 should not only have good positional accuracy and shape over a length close to 30 (-FF1), which corresponds to the array of light emitting points on the insulating substrate 1, but also be electrically connected to the grid electrode 5 and the anode 2a. It is necessary that there be no pinholes to prevent touching.Additionally, if there is fluorescent material or conductive dust in the gap 9 between the grid electrode 5 and the insulating substrate 1, the grid electrode 5 and the anode 2a Since a touch occurs on □, it is desirable that the thickness of the insulating layer 4 is thicker.

[Problem that the invention seeks to solve]

However, in the conventional fluorescent light source tube described above, the insulating layer 4 is formed by a screen printing method, and therefore has the following problems. In other words, ■ an elongated slit-shaped opening 10 due to expansion and contraction of screen plate making, etc.
cannot be formed accurately. - Repeated positioning accuracy with the light emitting point array is poor due to the mechanical precision of the printing machine. ■To prevent the insulating paste from sagging after printing and to increase the thickness,
Fillers are added to the paste. For this reason, pinholes are likely to occur (printing with insulating paste without filler addition causes sagging and is completely unusable). These problems have caused a decline in yield and reliability in manufacturing.

The present invention has been made in view of these circumstances, and provides a fluorescent light source tube with improved yield and reliability by having an insulating layer in a multilayer structure and arranging a grid electrode on the insulating layer. This is what we provide.
[Means for solving the problem] The fluorescent light source tube according to the present invention forms a light-emitting point using a phosphor coated on an anode formed on an insulating substrate. By arranging a plurality of light emitting points in one direction to form a row of light emitting points and selecting an arbitrary anode lead drawn out to the outside of the vacuum vessel on the insulating substrate, an anode extending on this anode can be formed. In a fluorescent light source tube in which the upper phosphor emits light by cathodoluminescence, the phosphor is formed so as to be exposed along the arrangement direction of the phosphor on the anode constituting the light emitting point array on the insulating substrate. A plurality of insulating layers each having a slit-like opening are provided, and a grid electrode having a slit-like opening corresponding to the opening is stacked on the insulating layer. be.

[Effect]

In the present invention, a plurality of insulating layers having slit-like openings are formed in the direction in which the phosphors on the anode constituting the light emitting point array on the frame substrate are arranged, and grid electrodes 5 are formed on this insulating layer. By arranging them one on top of the other, there are fewer pinholes in the insulating layer, and the positional accuracy of the grid electrode on the insulating layer is improved, making it possible to reduce electrical contact between the grid electrode and the anode. .

〔Example〕

The present invention will be explained below based on actual cases shown in the drawings.

1 and 2 are a sectional view and a plan view thereof corresponding to FIG. 5 showing an embodiment of the fluorescent light source tube according to the present invention,
The same reference numerals as in FIGS. 3 to 5 indicate the same or corresponding parts. The difference between the fluorescent light source tube of this embodiment and the conventional one described above is that the fluorescent light source tube of this embodiment is different from the conventional one described above.
A first insulating layer 7 having a slit-shaped opening 12 is formed along the arrangement direction of the upper phosphors 3 to expose the phosphors 3 by an exposure method. A second insulating layer 8 having slit-shaped openings 13 is formed by a printing method to form a two-layer structure, and grid electric pictures 5 having slit-shaped openings 11 are stacked on top of this insulating layer 8. This is what we decided to do. In this case, the insulating layer 1 has a slit-shaped opening (hereinafter referred to as slit) 12 formed in the insulating layer 8, which has a slit 12 stacked thereon.
3, the formation field is closer to the light emitting point array side of the phosphor 3. In addition, the grid pole 5 has slits 11 in the insulating layer 8.
The slit 13 approaches the light emitting point row side and projects out like sunlight. In addition, the symbols 7 and 8 in the figure
, indicates the end of the slit portion of each of the insulators NJ7 and 8, and symbol 5□ indicates the end of the slit portion of the grid "aLis."

Next, a method for forming each of the above-mentioned insulating layers 7.8 will be specifically explained. First, amorphous glass that does not contain fillers is used as an insulating material with few pinholes, and a plurality of anode/external leads 2 (see Fig. 4) are arranged side by side on an insulating substrate 1 on which an anode pattern is formed. The second insulating layer 7 is formed by an exposure method.

That is, using a water-soluble photoresist (for example, a diazo type photoresist), a pattern of 7 photoresists is formed in a line on the anode 2a by exposure in the same direction as the phosphor in a width wider than the width where the phosphor 3 is formed. is formed with a thickness of 10 to 20 μm. Next, an amorphous glass paste containing no oil-based filler is formed by screen printing, and after drying, the water-soluble photoresist is removed by washing with water, and the insulating layer on this pattern is removed together. (The so-called lift-off method). Now the insulating layer I with the slit 12
A pattern is formed. At this time, since the insulating layer 7 has been dried and solidified, no sagging occurs even if it does not contain filler. Thereafter, it is vitrified by firing to form an insulating layer 7 with a thickness of about 10 μm. By forming the amorphous glass paste containing no filler by the exposure method in this manner, the insulating layer 7 having the slits 12 with few pinholes and high positional accuracy can be formed.

Next, an insulating layer 8 is laminated by a printing method on the first insulating layer 7 formed in this manner.

This means that when the K1ff contact grid electrode 5 is stacked on one insulating layer as in the past, (1) the thickness of the insulating layer is ~1
It is thin, about 0 μm, and is easily touched at the position of the gap 9 on the phosphor side. In addition, (11) the amorphous glass layer itself has very few pinholes, but if there is dust on the substrate, problems such as pinholes will occur as a result.
In order to solve this problem, an insulating layer 8 is stacked on the insulating layer 7 to form a two-layer structure. That is, on the first insulating layer 7 having the slits 12, a normal insulating glass paste made of an amorphous glass material and fillers such as fart and 03 particles is formed by a normal screen printing method, and then By firing, an insulating layer 8 having slits 13 is formed with a thickness of about 20 μm. In this case, the width of the slit 13 of the second insulating layer 8 is larger than the slit width of the first insulating layer 7 with a margin, since the first insulating layer 7 with good pattern accuracy has already been formed. It can be relatively wide, and the pattern accuracy can be relatively rough. Furthermore, since the first insulating layer 7 has few pinholes, even if there are some pinholes in the second insulating layer 8, it is extremely rare for the pinholes in the insulating layers 7 and 8 to overlap. be.

Taking an example of a slit having a length of about 300 mm in the insulating layers 7 and 8 formed in this way, in the first layer 7, the width of the slit 12 is 150±10 μm, and the light emitting point array of the phosphor 3 is shown. The parallelism with the center line is very good (10 μ on the center line)
The deviation was within m). In addition, the second layer 8 has slits 13
The width is 350 mm and the deviation on the center line is 100 μm.
It was within m.

Next, these first. A grid electrode 5 having slits 11 stacked on second insulating layers 7 and 8 will be described. This grid electrode 5 is for effectively guiding electrons from the cathode 6 onto the phosphor 3. Therefore,
It is necessary to stack grid electrodes 5 having precisely narrow slits (usually about 150 μm) 11 with high positional accuracy. For this reason, alignment is performed on the insulating layer, but if the insulating layer 4 is one layer as shown in FIG. So,
It is easy to hit the fluorescent surface during alignment of the grid electrode. Further, when the insulating layer 4 is exposed in the slit 11 of the grid electrode 5, electrons from the cathode 6 accumulate there (charge up), and the emission intensity decreases. Therefore, in order to form the insulating layer 4 so that it is not exposed, the slit 100 must be
If a margin is provided for the width, there is a problem in that many touches occur in the portion 9 due to phosphor residue between the grid electrode 5 and the substrate 1. For example, the slit 11 of the grid electrode 5 has a diameter of 150 μm.
Insulating layer 4 formed by screen printing when m is used.
is slit width 300±25μm1 pre-50 on center line
μm is required. This is a very difficult dimensional accuracy. In the grid electrode 5 stacked on the insulating layers 7 and 8 of the two-layer structure according to the present invention, +11 the width of the slit 110 of the grid electrode 5 is approximately the same as the width of the slit 12 of the first insulating layer 7. This makes grid alignment easier and more accurate.

(2) The surface of the insulating layer 8 can be made higher than the surface of the phosphor, and the phosphor 3 is not touched during positioning of the grid electrode 5.

(3) Even if the width of the slit 13 of the second insulating layer 8 is wide, the residue portion 91 remaining between the sunlight part of the grid electrode 5 and the top of the substrate 1 is one side of the first insulating layer 7. Therefore, there will be no electrical touch.

It has advantages such as:

In addition, although the above-described embodiment shows the case where one layer is further laminated on the first insulating layer T, it goes without saying that two or three layers may be laminated.

Further, although the first insulating layer 7 is a thick film insulating layer formed by a lift-off method using glass paste, it may be any insulating layer with high precision with few pinholes.
For example, 8%02, A/
, 20B or the like may also be used.

〔Effect of the invention〕

As explained above, according to the fluorescent light source tube according to the present invention,
By providing a structure in which a plurality of insulating layers having slits are provided in the arrangement direction of the phosphors on the anode constituting the light emitting point array on the insulating substrate, and a grid electrode is arranged on this insulating layer, the insulating layer The number of pinholes is reduced, the processing accuracy is improved, and the positional accuracy of the grid electrode on the insulating layer is improved. This has the effect of reducing electrical contact between the grid electrode and the anode, improving yield and reliability.

[Brief explanation of the drawing]

1 and 2 are a new main part diagram and a plan view thereof showing an embodiment of the fluorescent light source tube according to the present invention, and FIG. 3 is a plan view showing the substrate structure of a conventional fluorescent light source tube, and FIG. 4 is an enlarged plan view showing a part of the anode and external lead of FIG. 3, and FIG. 5 is a sectional view of a conventional fluorescent light source tube. 1...Insulating substrate, poor...Anode/external lead, 2
a...positive-", 3...fluorescent material, 5...
Grid electrode, 6... cathode, 7... first layer insulating layer, 8... second layer insulating layer, 11...
Slit-shaped opening (slit), 12.13...
A slit-shaped opening (slit).

Claims (2)

[Claims] (1) A light-emitting point is formed by a phosphor coated on an anode formed on an insulating substrate, and a plurality of light-emitting points are arranged in one direction to form a light-emitting point row, and a light-emitting point is formed on the insulating substrate. By selecting an arbitrary anode lead drawn out of the vacuum container, a light emitting point on the insulating substrate can be set in a fluorescent light source tube in which a phosphor on an anode extending from the anode lead emits light by cathodoluminescence. A plurality of insulating layers having slit-like openings formed to expose the phosphors on the anodes constituting the row are provided, and the first layer of the insulating layer is A grid electrode having an opening formed closer to the light emitting point array than an opening in an insulating layer stacked above the grid electrode, and having a slit-like opening formed on the insulating layer in correspondence with the opening. A fluorescent light source tube characterized by being provided in a stacked manner. (2) The first insulating layer among the plurality of insulating layers is formed by an exposure method using an amorphous glass material, and at least one of the insulating layers on the first layer is made of an amorphous glass material. 2. The fluorescent light source tube according to claim 1, wherein the fluorescent light source tube is formed by a printing method using a material containing a filler.