JPS60160553A - Phosphor discharge tube for display - Google Patents

Abstract

PURPOSE:To obtain a phosphor discharge tube of quick response while working for a long life, high efficiency and low cost by making at least one side of the electrodes to be a hollow electrode while applying or baking a metal oxide to its inside and coating said metal oxide with mercury. CONSTITUTION:The hollow electrodes 3 and 4 are so formed that a metal oxide such as an alkaline metal and alkaline earth metals is applied or baked to the inside of the respective cylinders while coating said metal oxide with mercury. Inside the bent part of the tubular body 1 an auxiliary electrode 5 is held while its tip penetrates the tube wall. Microdischarge is made to be constantly performed between the hollow electrodes 3, 4 and the auxiliary electrode 5 through an auxiliary discharge circuit. When oscillation voltage is impressed between the hollow electrodes 3 and 4, the main discharge is easily generated because the auxiliary discharge is generated just in the central part of the discharge tube thus immediately performing stable discharge. Accordingly, quick response can be obtained together with little sputtering and a long life of the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a display fluorescent discharge tube used, for example, in a color display such as an electronic bulletin board.

[Technical Background of the Invention and Problems Therewith] Conventionally, light sources using light bulbs or color cathode ray tubes have been known as display light sources used for color displays such as electronic bulletin boards. however,
Those using light bulbs had the disadvantage of poor efficiency and slow response, and those using color cathode ray tubes had quick response, but had disadvantages of poor efficiency, high cost, and high voltage requirements.

Therefore, it is conceivable to use a hot cathode type fluorescent lamp as a light source. In other words, fluorescent lamps have a quick response and are extremely efficient compared to light bulbs and cathode ray tubes.
Moreover, it has advantages such as low cost. but,
Hot cathode type fluorescent lamps use an electrode preheating method, and when a discharge is generated between the electrodes during rapid blinking operation, a high-energy group of ionized electrons collides with the electrodes, causing emitter scattering and sputtering. There is a problem of shortening the life of the electrode.

[Purpose of the Invention] This invention was made to solve these problems, and provides a fluorescent discharge tube for displays that has a quick response, has a longer lifespan, is highly efficient, and can be lowered in cost. The purpose is to provide.

[Summary of the Invention] This invention provides a method in which a pair of electrodes are arranged at each end of a tube, at least one of the electrodes is a hollow electrode, and the inner surface of the hollow electrode is coated with a metal oxide such as an alkali metal or an alkaline earth metal. Or, it is fired and the metal oxide is coated with mercury.

Further, the present invention is provided with an auxiliary electrode for starting.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a fluorescent discharge tube according to the present invention, where 1 is a U-shaped housing, and 2 is a phosphor coated on the inner wall of the tube body 1. As shown in FIG. Hollow cylindrical hollow electrodes 3.4 are attached as main electrodes to both ends of the tube body 10, respectively. The hollow electrode 3.4 has an alkali metal, an alkaline earth metal, etc. (for example, barium oxide, aluminum oxide, silicon oxide, sodium oxide, etc.) on the cylindrical inner surface.

) is coated or fired, and mercury is deposited on the gold B and R oxides. An auxiliary electrode 5 is held inside the bent portion of the tube body 1 with its tip penetrating the tube wall.

FIG. 2 is a circuit diagram for controlling the lighting of the fluorescent discharge tube of FIG. 1, where A is a main circuit section, B is a control circuit section, and C is an auxiliary discharge circuit section. The main circuit section A is provided with a pair of NPN transistors 6 and 7 and an oscillation transformer 8, and the emitters of transistors 1 to 7 are connected to the negative terminal of the power supply.
A collector is connected to each end of the primary winding 81 of the oscillation transformer 8, respectively. The oscillation transformer 80 primary winding 1
A capacitor 9 is connected in parallel to 81. Said 1
The middle tap 8t of the next winding 81 is connected to the inductance coil 1.
It is connected to the positive terminal a of the power supply via 0. The oscillation transformer 8 is provided with a base winding 83, one end of which is connected to the base of the transistor 6, and the other end connected to the base of the transistor 7. The bases of each of the transistors 6.7 are also connected to the positive terminal a of the power supply through resistors 11.12, 13.14, and the inductance coil 10 commonly connected in series. That is, the main circuit section A is composed of a well-known high frequency inverter circuit. The hollow electrodes 3.4 of the discharge tube are connected to the output terminals of the main circuit section A, that is, to the terminals of the secondary winding 82 of the oscillation transformer 8, respectively.

The control circuit section B is the tertiary winding m84 of the oscillation transformer 8.
The AC input terminal of a diode bridge circuit 15 for full-wave rectification is connected to the AC input terminal of the diode bridge circuit 15 for full-wave rectification, the positive side of the rectified output terminal of the bridge circuit 15 is connected to the connection point of the resistors 13 and 14 via the resistor 16, and the negative side is connected to NPN type 1 helangister 1
It is connected to one d of the emitter and control input terminal of 7. The collector of the transistor 17 is connected to the resistor 13.1.
4, and its base is connected to the other control input terminal C via a resistor 18.

The auxiliary discharge circuit C includes NPN type 1 to transistors 19, 20, . . . like the main circuit section A. Oscillation transformer 21, capacitor 22, inductance coil 23, resistor 24.25
．． 26, one end of the secondary winding m212 of the oscillation lance 21 is connected to the auxiliary electrode 5, and the other end is connected to the secondary winding 82 of the oscillation transformer 8 to the main circuit section. It is connected to the connection point between the other end and the hollow electrode 4. Note that e and f are input terminals of the power supply.

In the apparatus according to the present invention constructed in this manner, first, the auxiliary discharge circuit C causes a slight discharge to occur between the hollow electrode 3.4 and the auxiliary electrode 5 and between the ground point and the auxiliary electrode 5 at all times. In this state, the oscillation voltage by the main circuit section A is applied between the hollow electrodes 3 and 4 under the control of the control circuit section B. At this time, since the auxiliary discharge is generated exactly in the center of the discharge tube, the main discharge is easily generated and stable discharge is immediately performed. Therefore, the response is quick, and there is less spatter on the electrodes, resulting in a longer life. Furthermore, since a fluorescent discharge tube is used, efficiency can be improved and a high-intensity discharge tube can be obtained. Furthermore, even if the electrode material or metal oxide is sputtered, since the electrode is a hollow electrode, it will re-adhere to the inner wall surface of the cylinder, resulting in extremely little wear and tear. Furthermore, since mercury is deposited on the surface of the metal oxide, a cathode spot is easily formed at the contact area between the mercury surface and the metal oxide surface, and the glow discharge time can be extremely shortened to the extent that it can be ignored. Discharge can be easily performed. Therefore, it is suitable for large current discharge, and a high-brightness color display board in which a large number of discharge tubes, which is the present device, are assembled can be easily formed. It is also resistant to pulsed discharge, and is particularly effective when controlling the brightness of color display discharge tubes by pulse width control. Furthermore, since the auxiliary electrode 5 is attached inside the bent portion of the tube body 1, the auxiliary discharge light is less likely to leak in the viewing direction, and a sufficient brightness contrast can be obtained. Furthermore, costs can be reduced compared to those using color cathode ray tubes.

In the above embodiment, the auxiliary discharge using the auxiliary N pole is always performed, but the invention is not necessarily limited to this. For example, the auxiliary discharge is performed without generating pulses only when a control input is input to the control circuit section B. It is also possible to cause the discharge to occur. In addition, in the above embodiment, a pair of hollow electrodes were coated or fired with metal oxide on the inner surface and mercury was coated, but the invention is not limited to this, and in the case of direct current discharge, the cathode Only the hollow electrode on the side has this configuration, and the cathode side does not necessarily have this configuration.

Next, another embodiment of the invention will be described with reference to the drawings.

Note that the same parts as in the above embodiment are given the same reference numerals, and detailed explanations will be omitted.

First, in the one shown in FIG. 3, the tip of an auxiliary electrode 51 is attached to the outer wall inside the bent part of the tube body 1. In this one, the auxiliary electrode becomes an external electrode and high-frequency electrodeless discharge is performed. The same effects as those of the above embodiments can also be obtained in other products.

Furthermore, in the case shown in FIG. 4, auxiliary electrodes 52,53 are provided inside the pair of hollow electrodes 3,4, and the same effects as in the above embodiment can also be obtained in this case. .

Although an auxiliary electrode was provided in the above embodiment, this auxiliary electrode is not necessarily necessary, and even if there is no auxiliary electrode, the small row electrode can be coated or fired with a metal oxide and coated with mercury. The effects of the above embodiments were fully obtained,
The auxiliary electrode has the effect of further enhancing this effect.

Effects of the Invention F As described in detail above, according to the present invention, it is possible to provide a fluorescent discharge tube for a display that has a quick response, has a long life, is highly efficient, and is low in cost.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a lighting control circuit diagram of a discharge tube according to the present invention, and FIGS.
The figure is a configuration diagram showing another embodiment of the present invention. 1... tube body, 2... phosphor, 3.4... hollow electrode, 5... auxiliary electrode. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A pair of electrodes is arranged at each end of the tube, at least one of the electrodes is a hollow electrode, and a metal oxide such as an alkali metal or alkaline earth metal is coated or fired on the inner surface of the hollow electrode, and A fluorescent discharge tube for display use, characterized in that the metal oxide is coated with mercury. (2) A pair of main electrodes are arranged at each end of the tube, and an auxiliary electrode for starting is provided, at least one of the main electrodes is a small low electrode, and the inner surface of the hollow electrode is made of an alkali metal, an alkaline earth metal, etc. 1. A fluorescent discharge tube for a display, characterized in that a metal oxide is coated or fired, and the metal oxide is coated with mercury.