JPS636981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a novel fluorescent light source tube that eliminates the need for a grid. Usually, a fluorescent light source tube with a large number of light emitting points arranged in one direction is used as a light source for facsimiles or a light source for copying machines.

FIG. 1 is a plan view showing a conventional fluorescent light source tube. In the same figure, 1 is an insulating substrate, and 2 is an insulating substrate whose details are shown in FIG. As shown in FIG. 3, a plurality of anodes/external leads 3 arranged above are connected to one end 2 of this anode/external lead 2.
4 is an insulator layer (see Figure 3);
1 is a grid stretched over the phosphor 3 forming an array of light-emitting points, 6 is a cathode stretched over this grid 5, 7 is a face glass sealed to the insulating substrate 1 to form a vacuum container, and 8 is a It's an exhaust pipe.

Next, the operation of the fluorescent light source tube with the above configuration will be briefly explained. First, thermionic electrons are extracted from the heated cathode 6 by the grid 5 being positively biased with respect to the cathode 6. and,
When an arbitrary anode/external lead 2 drawn out of the vacuum chamber is selected and biased positively with respect to the cathode 6, electrons passing through the grid 5 enter the phosphor 3 on the selected anode 2a. Therefore, the phosphor 3 emits light.

However, in a typical case where the conventional fluorescent light source tube has a light emitting point size and pitch of 0.1 x 0.05 m/m and 0.1 m/m, and a number of light emitting points (fluorescent bodies 3) is 2046, for example, , line width l of grid 5 (third
(see figure) is approximately 0.02 to 0.05m/m. For this reason, some of the light emitting points (phosphor 3) overlap with the grid 5, which causes the light emitting points to be missing or blurred. In addition, the distance d between the grid 5 and the light emitting point (phosphor 3) (see Figure 3) greatly affects the light emission state, and since the grid 5 is thin and very long, this distance d must be kept constant. It is difficult to do so. Further, the area of light emitted by electron irradiation is smaller than the grid 5, and since the grid 5 is located on the cathode side, most of the electrons from the cathode 6 flow to the grid 5, so-called current efficiency from the cathode is poor. On the other hand, even if the cathode 6 is located directly above the light emitting point, the distance from the light emitting point is large, so the cathode 6 does not blur the light emitting point. Furthermore, if the cathode 6 is stretched a little apart from directly above the light emitting point, the effect will be further reduced. In this way, the grid 5 causes the light emitting point to be missing or blurred,
There were drawbacks such as poor lighting conditions.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fluorescent light source tube which can eliminate the lack of or blurring of light emitting points due to grids and can provide good light emitting conditions.

In order to achieve such an object, the present invention includes a pair of extraction electrodes disposed on both sides of the luminescence point array in the direction along the luminescence spot array, and a pair of extraction electrodes disposed on both sides of the luminescence spot array on the opposite side of the luminescence spot array. a pair of focusing electrodes arranged along the row of light emitting points are formed on the insulating layer formed on the anode, and a positive bias is applied to the pair of extraction electrodes with respect to the cathode;
A negative bias is applied to the pair of focusing electrodes with respect to the cathode, and will be described in detail below using examples.

FIG. 4 is a plan view showing an embodiment of the fluorescent light source tube according to the present invention. In the same figure, 9a and 9
Denoted by b are extraction electrodes arranged on both sides of the phosphor 3 arranged in a large number in one direction, and 10a and 10b are focusing electrodes arranged on the outside of the extraction electrodes 9a and 9b.

Note that the width of the focusing electrodes 10a and 10b is as shown in FIG.
It is narrower than the width of b, and is formed to have a width of 1/2 to 1/10, for example. In addition, these extraction electrodes 9a and 9
b. The method of forming the focusing electrodes 10a and 10b may be, for example, by forming the insulating layer 4 on the anode by thick film printing, and then further forming Ag or graphite on the insulating layer 4 by thick film printing. , _Al may be formed by sputtering.

Next, the operation of the fluorescent light source tube having the above configuration will be explained with reference to FIGS. 6a and 6b. First, the extraction electrodes 9a and 9b are positively biased with respect to the cathode 6 (see FIG. 3), and an arbitrary anode/external lead 2 drawn out outside the vacuum vessel is selected, and the lead electrodes 9a and 9b are biased positively with respect to the cathode 6. When biased, thermionic electrons 11 extracted from the heated cathode 6 flow as shown in FIG. 6a. When a negative bias is applied to the focusing electrodes 10a and 10b with respect to the cathode 6, the thermoelectrons 11 extracted from the cathode 6 are drawn toward the anode 2a, as shown in FIG. 6b.
Therefore, the current density flowing into the phosphor 3 increases, and the current efficiency increases.

Note that since the focusing electrodes 10a and 10b are on (or near) the insulating substrate 1, the negative bias effect occurs near the substrate surface and does not affect the amount of electrons extracted from the cathode 6. In addition, extraction electrodes 9a and 9b, focusing electrodes 10a and 10b
It goes without saying that etched metal may be pasted onto the focusing electrodes 10a and 10b, or L-shaped metal parts pressed into the focusing electrodes 10a and 10b may be used as shown in FIG.

As explained in detail above, according to the fluorescent light source tube according to the present invention, (a) chipping or unevenness of light emitting points is eliminated, (b) light emission intensity becomes uniform, (c) current efficiency increases, This has effects such as improved luminance.

[Brief explanation of the drawing]

Figure 1 is a plan view showing a conventional fluorescent light source tube;
The figure is a detailed plan view showing the anode/external lead of Fig. 1, Fig. 3 is a sectional view taken along line AA of Fig. 1, and Fig. 4 is a plan view showing an embodiment of the fluorescent light source tube according to the present invention. figure,
5 is a sectional view taken along line BB' in FIG. 4, FIGS. 6a and 6b are diagrams for explaining the operation of FIG. 4,
FIG. 7 is a side view showing another example of the focusing electrode shown in FIG. 4. 1...Insulating substrate, 2...Anode and external lead, 2
a... Anode, 3... Fluorescent material, 4... Insulator layer, 5
... Grid, 6 ... Cathode, 7 ... Face glass, 8 ... Exhaust pipe, 9a and 9b ... Extraction electrode, 10a and 10b ... Focusing electrode, 1
1...Thermoelectron.

Claims (1)

[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 lined up in one direction to form a row of light-emitting points, and outside the vacuum vessel on the insulating substrate. By selecting an arbitrary anode lead from among the anode leads pulled out, the phosphor on the selected anode emits light by cathodoluminescence in the fluorescent light source tube in the direction along the light emitting point row. A pair of extraction electrodes placed on both sides of the light emitting point row, and a pair of focusing electrodes placed along the light emitting point row on both sides of the extraction electrode on the opposite side of the light emitting point row are placed on the anode. A fluorescent light source tube is formed on an insulating layer formed on an insulator layer, and wherein a positive bias is applied to the pair of extraction electrodes with respect to the cathode, and a negative bias is applied to the pair of focusing electrodes with respect to the cathode. .