JPS6286643A - Fluorescent character display ture - Google Patents

Abstract

PURPOSE:To reduce the influence of an end cooling effect to the utmost, by equipping an auxiliary cathode filament being stretched as crossed in and around an end part of a cathode filament apart from it, and the part projected from the cathode filament situated at the outermost side is bent. CONSTITUTION:For an end cooling effect, almost no electron is emitted out of the end par being attached to an arm part 27 of a cathode filament 21 and absorbed of its heat. But, at a slight lower part of the cathode filament end part, the central part of an auxiliary cathode filament 22 is situated in a direction nearly orthogonal with the cathode filament 21, and both ends of the auxiliary filament 22 are hung on holding members 29 and 29, bent at about 90 deg.C and both these ends are attached to arms 28a and 28b. With this constitution, since sufficient electrons in quantity are emitted without causing any end cooling effect, the required quantity of electrons is projected to even the image element set up at the end part.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to fluorescent light, which is widely used in home appliances such as VTRs and audio equipment, or as in-vehicle display devices such as speed display and remaining fuel level display of automobiles. The present invention relates to display tubes, and particularly relates to a fluorescent display tube that can be applied to a case where a large number of fluorescent display tubes are combined to form a single display device, so that the display size can be increased relative to the external size.

[Prior Art] Generally, a fluorescent display tube has a structure as shown in FIG. An insulating layer 3 having through holes is formed on the upper surface thereof.

Furthermore, an anode conductor 4 is arranged in an arbitrary pattern on the upper surface of the insulating layer 3, and the anode conductor 4 is connected and electrically connected to the wiring conductor 2 via the through hole. A phosphor 5 is deposited on the anode conductor 4 to form an anode 6.

On the other hand, above the anode 6, a cathode filament 8 is stretched between supports 7 and 7, and thermoelectrons are emitted by heating the cathode filament 8 with electricity. A control electrode 9 is disposed between the cathode filament 8 and the anode 6 to accelerate and control the electrons emitted from the cathode filament 8, causing them to strike the phosphor 5 of the anode 6 to which a display signal has been applied, thereby producing a desired result. A fluorescent display can be obtained.

[Problems to be Solved by the Invention] By the way, the cathode filament 8 is configured to emit electrons from a resistive material on the surface by heating a core wire made of a thin tungsten wire with electricity. However, since the cathode filament 8 is stretched with both ends connected to the support 7.7, the heat generated in the thin tungsten wire escapes to the support 7 near both ends of the cathode filament 8. As a result, the temperature at both ends of the cathode filament 8 decreases, and almost no thermoelectrons are emitted. (This series of phenomena is called the end-cooling effect.) Therefore, even if anodes are placed near both ends of the cathode filament 8, sufficient luminance cannot be obtained because the amount of electrons that should be emitted is insufficient. Alternatively, in conventional fluorescent display tubes, non-light-emitting portions occur.
There is a problem in that the display area becomes small relative to the outer diameter dimension, and in order to secure the necessary display area, the outer diameter dimension becomes large, resulting in restrictions on the installation space.

In particular, when making a unit of fluorescent display tubes and combining a large number of them to form a single display device, if the display area is small relative to the outer diameter, the non-light-emitting areas between each unit will be noticeable, making it difficult to use a high-definition display device. This poses a major problem in realizing this.

In order to reduce the negative effect on the display due to the end cooling effect of the cathode filament, as shown in Fig. 4,
In some cases, the auxiliary cathode filament 10.10 is arranged at both ends of the main cathode filament 8a so as to be substantially perpendicular to the stretching direction to secure the necessary amount of electrons.
The four corner portions indicated by circles B in the figure are still affected by the end cooling effect of the cathode filaments 8a and 10.

[Object of the Invention] The present invention minimizes the influence of the end cooling effect of the cathode filament, allows every corner of the fluorescent display tube to be used as a display area, and reduces the display area relative to the outer diameter of the fluorescent display tube. The purpose is to expand.

[Means for Solving the Problems] In order to achieve the above object, the fluorescent display tube of the present invention includes a cathode filament having a cathode filament which intersects with the cathode filament in the vicinity of the end thereof, at a distance from the end of the cathode filament.
It is characterized in that it includes an auxiliary cathode filament whose portion protruding from the outermost cathode filament is bent and stretched.

[Function] Almost no electrons are emitted near the end of the stretched cathode filament due to the end cooling effect. Therefore, the electrons emitted from the auxiliary cathode filament impinge on the anode disposed below the end of the cathode filament.

In addition, the amount of electrons emitted at both ends of the auxiliary cathode filament is also reduced due to the end cooling effect, but the auxiliary cathode filament is stretched with both ends bent, so that the amount of electrons emitted is small. Both ends are spaced apart from the end of the cathode filament.

Therefore, since the electrons reach every corner of the fluorescent display tube, the arrangement pattern of the anode is not restricted, and the display area can be expanded relative to the outer diameter of the fluorescent display tube.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a perspective view of a fluorescent display tube according to an embodiment, and FIG.
Figure (a) is a sectional view taken along line a-a in Figure 1, and Figure 2 (
b) is an enlarged sectional view taken along line bb in Fig. 2(a), and Fig. 3 shows the cathode filament 2, which is the main part of this embodiment.
1 is a simplified diagram showing the positional relationship between the auxiliary cathode filament 1 and the auxiliary cathode filament 22. FIG.

As shown in FIGS. 1 and 2(a), the fluorescent display tube 13 of this embodiment is made of the same material on one surface of an anode substrate 14 made of a translucent insulating material (for example, glass). A container part 17 consisting of a side plate 15 and a back plate 16 is sealed and fixed to form a box-shaped envelope 18, and the inside of the envelope 18 housing various electrodes etc. is maintained in a high vacuum state. It is.

Anode conductors 19 and wiring conductors are formed in a predetermined pattern on the inner surface of the anode substrate 14, and on the upper surface of each anode conductor 19 are three types of phosphor layers r and g that emit light in red, green, and blue, respectively. , b are deposited to form an anode.

In this embodiment, one pixel RGB is composed of a total of nine anodes arranged in three rows and three columns each, and the anodes as constituent elements of the pixel RGB are particularly called R, G, and B. and,
Each pixel (RGB) emits a different color
, G, and B are included.

The pixels R, G, and B are arranged in a plurality of rows and columns in multiple locations on the anode substrate 14, including the area close to the side plate 15.

Next, a mesh-like control electrode 20 is disposed above the pixels RGB, and accelerates and controls electrons emitted from a cathode filament 21 and an auxiliary cathode filament 22, which will be described later, to provide a display signal. The pixel RGB (or the selected dot R, G, B) is made to collide with the pixel RGB (or the selected dot R, G, B).

Next, a metal support 2 is placed on the inner surface of the back plate 16 in order to stretch the cathode filament 21 as a cathode.
3.23 is provided. Each of the supports 23, 23 is formed into a roughly oval shape with a base 24, and a long piece 25 and a short piece 26 extending from both ends of the base 24 in a direction intersecting the base 24. . A terminal 26& is formed on the short piece 26 of one support 23 and is led out to the outside of the envelope 18 in an airtight manner.
A terminal 25a is formed on the long piece 25 of the envelope 1.
8 is led out to the outside in an airtight manner.

Both supports 23.23 are arranged along the edge of the back plate 16 so as to face each other. A plurality of arm portions 27 are provided at the base portions 24.24 of both supports 23.23, respectively.

A plurality of cathode filaments 21 are stretched between these arm portions 27 with their ends welded together.

Next, as shown in FIGS. 1 to 3, the long piece 2 of the support body 23 is
5 has an arm 2 shorter than the arm portion 27 at approximately the center thereof.
8a, and at the tip of the long piece 25,
An arm 28b having the same height as the arm 28a is formed.

Furthermore, holding members 29 and 29 are provided on the lower surface of both corner portions of the support body 23 (both ends of the base portion 24) and protrude slightly downward from the arm portions 27 of the cathode filament 21. One end of the auxiliary cathode filament 22 is fixed to an arm 28a formed approximately in the center of the long piece 25, and the center part is attached to holding members 29, 29 formed at both ends of the base 24. The other end is fixed to an arm 28b formed at the tip of the long piece 25 of the other support 23, and is stretched in a substantially U-shape.

In addition, as shown in FIG. 2, an auxiliary cathode filament 22
The central part of the auxiliary cathode filament 22 is stretched slightly below both ends of the cathode filament 21 at a predetermined interval, and both ends of the auxiliary cathode filament 22 are extended outward from the cathode filament 21 while being inclined in the vertical direction. It is stretched parallel to the cathode filament 21.

Similarly, the auxiliary cathode filament 22 is stretched over the other support 23, and the two auxiliary cathode filaments 22.22 are stretched approximately between the two supports 23.23.

The auxiliary cathode filament 22 has the same thickness and material as the cathode filament 21, and its length is set to be approximately the same as the total length of one cathode filament 21. Therefore, as shown in FIG.
3 terminal 26a.

Since the power source 30 for the cathode filament 21 connected between the cathode filament 25a and the cathode filament 25a can be directly used as a power source for the auxiliary cathode filament 22 without using an intermediate resistor or the like, the drive circuit can be simplified. Furthermore, an auxiliary cathode filament 22 and a cathode filament 21
Even if the lengths are different, you can make the resistance of both filaments the same by changing the thickness of the double-sided sword filament and the material of the core wire, or make the resistance of both filaments the same through a resistor. 30 can be used as a common power source.

Further, the holding member 29 is made of a material with low thermal conductivity, for example, an insulating material such as mica, or a material that has been subjected to an insulation treatment, and is configured to have a small contact area with the auxiliary cathode filament 22. ing. That is, as shown in FIG. 2(b), the holding member 29
are thin plate-like members, and each is attached to the lower surface of the support 23 at an angle of about 45° with respect to both directions in which the auxiliary cathode filament is stretched. Therefore, the contact with the auxiliary cathode filament 22 is close to a line contact, and it is difficult to absorb the heat of the auxiliary cathode filament 22, so the temperature drop at the contact part of the auxiliary force sword filament 22 is suppressed as much as possible, and the amount of electrons emitted is reduced. will not decrease.

Next, the operation of the configuration described above will be explained.

First, a predetermined voltage is applied to the cathode filament 21 and the auxiliary cathode filament 22 by the common power source 30. A sufficient amount of electrons are emitted from the center of the cathode filament 21 to cause the phosphor layers r, g, and b to emit light, but electrons are emitted from the ends attached to the arms 27 and receiving heat. Almost no electrons are emitted due to the edge cooling effect.

However, slightly below the cathode filament end,
Since the center of the auxiliary cathode filament 22 is located in a direction substantially perpendicular to the cathode filament 21 and emits a sufficient amount of electrons, the pixels RGB provided at the end of the anode substrate 14 emit light. The brightness will not decrease or the brightness will decrease.

Furthermore, both ends of the auxiliary cathode filament 22 are bent approximately 90'' by hanging on the holding member 29.29, and both ends are attached to the arms 28a, 28b. It is located outward from the outer cathode filament 21, and as described above, this part emits a sufficient amount of electrons without causing an end cooling effect.
The required amount of electrons will also be bombarded by the pixels RGB arranged at the four corners.

Further, both ends of the auxiliary cathode filament 22 are stretched between the holding member 29 and the arms 28a, 28b at an angle, and the closer the arms 28a, 28b are, the more the anode substrate 1
The gap between 4 and 4 becomes larger.

As shown in the second rgJ, the halves on the arms 28a and 28b side are located farther from the anode substrate 14 than the cathode filament 21.

Therefore, the electrons emitted from both ends of the auxiliary cathode filament 22 will not affect the RGB pixels disposed near the center of the anode substrate 14 and will not increase the brightness more than necessary.

As described above, the electrons emitted from the cathode filament 21 and the auxiliary cathode filament 22 are transmitted to the pixel RG.
B is necessary and sufficient to reach every corner of the anode substrate 14 where B is formed. Therefore, even if the pixels RGB are arranged in the corner or end near the side plate 15 as in this embodiment, it is sufficient. It is possible to obtain a high emission brightness, and to enlarge the display area relative to the outer dimensions of the fluorescent display tube 13.

[Effects of the Invention] As explained above, the fluorescent display tube of the present invention has an auxiliary cathode filament near the end of the cathode filament, which intersects with the cathode filament at a distance therefrom, and has both ends bent and stretched. Therefore, it is possible to obtain a sufficient amount of electron emission for light emission even at the corners of the fluorescent display tube, so there is an effect that the display size can be increased relative to the external size.

In addition, if the material of the auxiliary cathode filament is prepared in advance according to the resistance value of the main cathode filament, it becomes possible to drive the bi-power sword filament with - cathode filament power supplies, which saves power. There are effects that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
) is a cross-sectional view taken along the line a-a in FIG. 1, FIG. 2(b) is an enlarged cross-sectional view taken along the line b-b in FIG. 2(a), and FIG. Schematic diagram of a hailstorm, No. 4
The figure is a schematic diagram showing an example of the arrangement and connection relationship of cathode filaments in a conventional fluorescent display tube, and FIG. 5 is a structural diagram showing an example of the conventional fluorescent display tube. 13... Fluorescent display tube, 19... Anode conductor, 20...
・G II electrode, 21... cathode filament, 2
2... Auxiliary cathode filament, r, g, b...
Phosphor layer. Figure 3 1st

Claims (2)

[Claims] (1) A fluorescent display tube in which electrons emitted from a cathode filament are accelerated and controlled by a control electrode, and selectively strike a phosphor disposed on an anode conductor to obtain a desired luminescent display, wherein the cathode A fluorescent display tube comprising an auxiliary cathode filament which is arranged near the end of the filament so as to be spaced apart from and intersect with the filament, and whose part protruding from the outermost cathode filament is bent and stretched. . (2) A claim in which both bent ends of the auxiliary cathode filament are stretched in the stretching direction of the cathode filament, and the voltage applied to the auxiliary cathode filament is set to be approximately the same as the voltage applied to the cathode filament. The fluorescent display tube according to item 1.