JPH09213280A - Discharge display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply a phosphor highly effectively and simply, at a low discharge starting voltage, by making the cross section form in the vertical direction to the face plate of the discharge hole of a discharge display element, in a taper form expanding to a common cathode. SOLUTION: The inside of the discharge tube body 5 of a discharge display element 1 is partitioned into luminous small chambers 6a to 6d. At the bottom part of the luminous small chambers 6a to 6d, taper form of discharge holes 8a to 8d which are made as the discharge routes to a common cathode 2, and have a cross section form of inclination expanding to the common cathode 2, are provided. A phosphor 9 is applied to the inner wall surfaces of the luminous small chambers 6a to 6d. At the face plate side of the luminous small chambers 6a to 6d, anodes 7a to 7d which carry out the discharge selectively with the common cathode 2 respectively are provided. Consequently, the thickness of the minimum section area parts of the discharge holes 8a to 8d is made thinner, and the discharge is started easily. In this case, by providing a step at the common cathode 2 side of each discharge hole 8 so as to reduce the thickness of the discharge hole, the same effect can be obtained. The discharge display elements are aligned so as to form an image display device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge display element such as a fluorescent lamp for display used in a large-screen color display device for displaying images and information.

[0002]

2. Description of the Related Art Conventionally, a display device of this type is constructed by arranging a large number of discharge display elements 1 shown in FIG. 6 in a vertical and horizontal direction as shown in FIG. By appropriately controlling blinking, necessary information such as characters and figures is displayed.

The discharge display element 1 is a single tube that emits monochromatic or polychromatic light. As shown in FIGS. 5A and 5B, a cylindrical glass having a common cathode 2 and an auxiliary electrode 3 built therein. Above the bulb 4, a discharge tube body 5 having a quadrangular cross section that forms a light emitting portion is hermetically sealed by using, for example, low-melting glass, and the discharge tube body 5 has four light emitting chambers 6a,
It is divided into 6b, 6c, and 6d. At the other end of the discharge tube body 5, a face plate 10 made of soda glass, which constitutes a display surface, is hermetically sealed by using a low melting point glass or the like.

The light emitting chambers 6a to 6d are arranged such that the discharge paths formed therein are in a direction parallel to the tube axis of the glass bulb 4, that is, in a direction orthogonal to the face plate 10, and the cross-sectional shape of each chamber. Is composed of two types of tapered portions having different slopes that spread toward the face plate 10.

At the bottom of each of the light emitting chambers 6a to 6d, there are cylindrical discharge holes 8a, 8b, 8 which serve as discharge paths for the common cathode 2.
c and 8d are opened, and each light emitting small chamber 6a, 6b, 6
On the inner wall surfaces of c and 6d, for example, a phosphor 9 that emits green light to the light emitting small chambers 6a and 6c, red to 6b, and blue to 6d is applied, and the light emitting small chambers 6a, 6b, 6c, and 6d are coated. A common cathode 2 and anodes 7a, 7b, 7c and 7d for selectively discharging are provided at the end of the face plate side.

The discharge display element 1 is filled with argon as a starting gas and mercury, and the phosphor 9 is excited and emitted by ultraviolet rays of mercury generated by the discharge to perform display. Each light-emitting room 6
The light emitted by a, 6b, 6c and 6d is transmitted through the face plate 10 forming the display surface and radiated to the outside to obtain a full-color image or information.

The discharge tube body 5 is made of ceramics and is usually manufactured by press molding. In press molding, discharge holes 8
If the thickness in the direction parallel to the tube axis of is less than 2 mm, the discharge hole 8
Since the cracks are formed around the periphery of, the thickness of the discharge hole 8 needs to be 2 mm or more.

[0008]

In the conventional discharge display device, a discharge hole having a cross-sectional area smaller than that of the light emitting chamber is provided between the light emitting chamber and the common cathode in order to achieve high brightness and high contrast. Therefore, there is a problem that the discharge starting voltage becomes high and a high voltage is required at the time of starting.

Further, since the discharge hole has a small cross-sectional area, the tube wall load is large. Therefore, the power consumption in the discharge hole that does not contribute to light emission accounts for 20% of the total power consumption, and there is also a problem that the light emission efficiency is poor.

Further, when the phosphor is applied, the discharge hole is capped and the phosphor is filled from the face plate side, but the phosphor protrudes from the gap of the cap. For this reason, there is a problem that a phosphor removing step is necessary and the manufacturing process becomes complicated.

It is an object of the present invention to provide a discharge display device having a simple structure, a low discharge starting voltage, a high efficiency and a simple coating of a phosphor.

[0012]

To achieve the above object, according to the present invention, a cross-sectional shape of a discharge hole of a discharge display element in a direction vertical to a discharge plate is tapered so as to expand toward a common cathode. A step is provided on the common cathode side of the discharge hole.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a structure of a discharge display device showing an embodiment of the present invention. 1 (a) is a front view.
(b) is an AA 'cross section. In FIG. 1, the discharge display element 1 is a single tube that emits monochromatic or polychromatic light.
Above the cylindrical glass bulb 4 containing the common cathode 2 and the auxiliary anode 3, a ceramic discharge tube body 5 having a quadrangular cross section and forming a light emitting chamber is hermetically sealed using, for example, low melting point glass. The discharge tube body 5 is divided into four light emitting chambers 6a, 6b, 6c and 6d.
At the other end of the discharge tube body 5, a face plate 10 made of soda glass, which constitutes a display surface, is hermetically sealed by using a low melting point glass or the like.

The light emitting small chambers 6a to 6d are arranged such that the discharge paths formed therein are in a direction parallel to the tube axis of the glass bulb 4, that is, a direction perpendicular to the face plate 10, and the sectional shape of each small chamber. Is composed of two types of tapered portions having different slopes that spread toward the face plate 10. Note that a straight portion is provided on the upper end side of the tapered portion.

At the bottom of each of the light emitting chambers 6a to 6d, tapered discharge holes 8a, 8b, 8c, whose cross-sectional shape serving as a discharge path with the common cathode 2 expands toward the common electrode, are formed.
8d is provided, and each light emitting chamber 6a, 6b, 6c,
On the inner wall surface of 6d, for example, phosphors 9 that emit green light to the light emitting chambers 6a and 6c, red light to 6b, and blue light to 6d are coated, respectively, and the light emitting chambers 6a, 6b, 6c, 6 are formed.
A common cathode 2 and anodes 7a, 7b, 7c, 7d for selectively discharging are provided at the end of the face plate side of d.

The discharge display element 1 is filled with a starting gas of argon and mercury, and the phosphor 9 is excited and emitted by ultraviolet rays of mercury generated by the discharge to perform display. Each light-emitting room 6
The light emitted by a, 6b, 6c and 6d is transmitted through the face plate 10 forming the display surface and radiated to the outside to obtain a full-color image or information.

According to the discharge display element of the present invention, the cross-sectional shape of the discharge hole 8 in the direction perpendicular to the face plate is tapered so that the discharge hole 8 expands toward the common cathode. Becomes thinner. As a result, discharge is easily started, and a discharge display element having a low discharge start voltage can be obtained. Further, since the phosphor is not applied, the power consumption in the discharge hole that does not contribute to the light emission is reduced, and the light emission efficiency is improved. Further, when the phosphor is applied, by capping the discharge hole 8 in the same shape as the discharge hole, the contact surfaces are better meshed, and the protrusion of the phosphor can be prevented. As a result, the fluorescent substance removing step becomes unnecessary, and the workability of fluorescent coating is improved.

FIG. 2 is a vertical cross-sectional view of the main part of the discharge display device according to the second embodiment of the present invention. In this embodiment, a step portion 11 is formed on the side of the common cathode of the square pole discharge hole 8 and the discharge hole 8 is formed.
It is a reduction of the substantial thickness of. According to the configuration of the present embodiment as well, similarly to the above, the step of removing the phosphor with a low discharge start voltage and low power consumption is unnecessary.

FIG. 3 is a characteristic diagram showing the relationship between the discharge starting voltage (relative value) and the thickness of the discharge hole. The element specifications are anode-
The distance between the display anodes is 35 mm, and the argon pressure is 2,000 Pa. When the thickness of the discharge hole becomes shorter than 2 mm, the starting voltage drops sharply. Therefore, the thinner the discharge hole 8 is, the better.

In the above-mentioned embodiment, the shape of the discharge hole is a quadrangular prism, but the shape is not limited to this, and it may be cylindrical or polygonal. Further, as shown in FIG. 4, the stepped portion 11 may have a tapered shape or a polygonal pyramid shape. Furthermore, in the case of a tapered shape or a polygonal pyramid shape, the cross-sectional shape on the discharge hole side may be the same as the cross-sectional shape of the discharge hole.

[0021]

According to the present invention, the face plate of the discharge hole has a cross-sectional shape in the vertical direction which is tapered so as to expand toward the common cathode, or a step portion is provided on the common cathode side of the discharge hole. Since the thickness of the minimum cross-sectional area portion of the discharge hole is thin, the discharge is easy to start and a discharge display element having a low discharge start voltage can be obtained. In addition, the power consumption in the discharge holes that do not contribute to light emission is reduced, and the light emission efficiency is improved. Furthermore, when applying the phosphor, by capping the discharge hole with the same shape as the discharge hole, the contact surface can be better meshed and the protrusion of the phosphor can be prevented, so the phosphor removal step is not required. , Workability is improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a discharge display element according to the present invention.

FIG. 2 is an explanatory diagram of a main part showing a second embodiment of the discharge display element according to the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the discharge start voltage of a discharge display element and the thickness of a discharge hole.

FIG. 4 is an explanatory diagram of a main part showing a third embodiment of the discharge display element according to the present invention.

FIG. 5 is an explanatory diagram showing a conventional discharge display element.

FIG. 6 is a perspective view showing a discharge display element.

FIG. 7 is a perspective view showing a display portion of a display device using a discharge display element.

[Explanation of symbols]

1 ... Discharge display element, 2 ... Common electrode, 3 ... Auxiliary anode, 4 ...
Glass bulb, 5 ... Discharge tube body, 6 ... Light emitting chamber, 7 ... Display anode, 8 ... Discharge hole, 9 ... Phosphor, 10 ... Translucent face plate, 1
1 ... Step.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaiji Arai 888 Fujibashi, Ome City, Tokyo 888 Hitachi, Ltd. Heater Lighting Division (72) Inventor Yasushi Ikuta 888 Fujibashi, Ome City, Tokyo Heat, Hitachi Ltd. Vessel lighting division

Claims (2)

[Claims] 1. A discharge tube body having a translucent face plate forming a display surface, one or more discharge paths partitioned into the discharge tube body, and an inner wall surface forming each of the discharge paths. Each is coated with a phosphor, and is discharged between an independent electrode provided at one end of each of the discharge paths and a common electrode provided so as to oppose an independently provided discharge hole at the other end. In the discharge display element, the opening cross-sectional area of the discharge hole on the common electrode side is larger than the opening cross-sectional area on the discharge path side. 2. A video display device in which a plurality of the discharge display elements according to claim 1 are arranged.