JPH04133293A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To eliminate a diode so as to realize a small size, light weight, a low cost and high efficiency by providing a means for heating a cathode to a discharge start possible level at the time of voltage application between an anode and a cathode, and providing a luminous radiation electron tube itself with an operation of a diode. CONSTITUTION:When a switch element Q is turned on by a signal of a control circuit 5, an electric current flows in a closed loop comprising a DC power source E, and inductor L and the element Q while the current does not flow in a luminous radiation electron tube 1, and energy is stored in the inductor L in this time. Those are according to rectification of the electron tube 1 and when the element Q is off a current flows in the electron tube 1 by adopting the energy stored in the inductor L as a power source. A cathode 3 is heated beforehand to a state of possible starting by a current flowing in a closed loop comprising the power source E, a circuit of the cathode 3 and a resistor R1 in parallel, and a resistor R2, and the element Q is turned on/off to light the electron tube 1. A frequency of the control signal, on-duty and an L value are appropriately determined. Accordingly, a diode can be eliminated to realize a small size, light weight, a low cost and high efficiency.

Description

[Detailed Description of the Invention] Industrial Application Field] The present invention provides a discharge lamp that lights a light-emitting electron tube that emits light by colliding accelerated electrons with a light-emitting gas sealed in a tube to generate ultraviolet radiation. It is installed between the lighting device.

[Prior Art] A light-emitting electron tube has been proposed in Japanese Patent Application Laid-Open No. 57-130364, and this light-emitting electron tube 1 is a transparent electron tube with a light-emitting gas sealed inside, as shown in FIG. It is composed of a tube body 2 having optical properties, a thermionic emission type cathode 3 and an anode 4 disposed within the tube body 2, and the tube body 2
Inside, a light emitting gas such as mercury vapor is present at several 5 Torr.
This is because a low vacuum state exists to some extent.

In this light-emitting electron tube 1, electrons emitted from a thermionic-emitting cathode 3 are accelerated by an electric field caused by an electron acceleration voltage applied to the cathode 3 and four anodes, and the accelerated electrons are made of a material such as mercury vapor. By colliding with the light emitting gas, mercury vapor etc. are ionized and excited to cause ultraviolet radiation, and the ultraviolet rays are converted into visible light by the ultraviolet excitation type phosphor coated on the inner surface of the tube body 2, and the transparent Desired visible light is obtained through the tube body 2, and the light-emitting electron tube 1 is attracting attention as a compact, lightweight, low-cost, and highly efficient lamp.

A discharge lamp lighting device for lighting the light emitting electron tube 1 is installed in the fifth
It is shown in FIG.

The discharge lamp lighting device shown in FIG. 5 connects an AC power source e to a rectifier R.
The voltage of the DC power supply E obtained by rectifying and smoothing the DC power supply E using the DC power supply E and the smoothing capacitor C8 is stepped down by a step-down chopper circuit consisting of a switch element Q, a diode D, an inductor L, and a capacitor C, and then applied to the light-emitting electron tube 1. , the control circuit 5 performs on/off control of the switch element Q. In this discharge lamp lighting device, when the switch element Q is turned on, current flows through the DC power supply E, the inductor, the parallel circuit of the capacitor C, the light emitting electron tube 1, and the resistor R, and the closed loop of the switch element Q. Energy is stored and when the switch element Q is turned off, the inductor
The light-emitting electron tube 1 is turned on by repeating the operation in which a current flows using the energy stored in the inductor as a power source in a closed loop of a parallel circuit of a capacitor C, a light-emitting electron tube 1, a resistor R, and a diode D.

In FIG. 6, a buck-boost chopper circuit made of the same components is used instead of the buck chopper circuit described above. In this discharge lamp lighting device, when the switch element Q is turned on, the DC power supply E,
Inductor, current flows through the closed loop of switch Q to store energy in the inductor, and when switch element Q is off, the inductor is closed loop of parallel circuit of diode D, capacitor C, light emitting electron tube l, and resistor R. The light-emitting electron tube 1 is lit by repeating the operation in which a current is passed through the light-emitting electron tube 1 using the energy stored in the inductor as a power source.

In any of the above-mentioned discharge lamp lighting devices, by appropriately setting the frequency of the control signal of the switch element Q, the on-duty, and the inductance value of the inductor L,
Desired power can be supplied to the light emitting electron tube 1.

Note that the resistor R is provided to supply current to the thermionic emission type cathode 3 to heat it.

[Problems to be Solved by the Invention] By the way, in the discharge lamp lighting device for lighting the above-mentioned compact, lightweight, low-cost, and highly efficient light-emitting electron tube 1, it goes without saying that it is small, lightweight, low-cost, and High efficiency is required. However, in the chopper-type discharge lamp lighting device shown in FIGS. 5 and 6 above, the power loss in the diode D is large and a heat sink must be installed, which results in a larger size and increased cost. Moreover, there is a problem of poor efficiency.Is:.

The present invention has been made in view of the above points, and its object is to provide a discharge lamp lighting device for lighting a light-emitting electron tube that is small, lightweight, low cost, and highly efficient.

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a series circuit of an inductor and a switching element that is controlled on and off to a DC power supply, and connects the anode to the negative pole side of the DC power supply. A light emitting electron tube is connected in parallel to an inductor, and heating means is provided for heating the cathode to a level at which discharge can start when a voltage is applied between the anode and the cathode in the direction in which current flows from the anode to the cathode.

Effect] The present invention focuses on the rectifying effect of the light-emitting electron tube, and
The light-emitting electron tube itself has the function of a diode, which was a cause of increased size, increased cost, and decreased efficiency, making it possible to omit the diode, resulting in a smaller size, lighter weight, lower cost, and higher efficiency. This is what I did.

U example] An embodiment of the present invention is shown in FIGS. 1 and 2. FIG.

The discharge lamp lighting device of this embodiment also rectifies and smoothes the AC power source e with the N current device Re and the smoothing capacitor C0 to obtain a profitable DC power ml!
[It operates using E as a power source, and this DC power NE
An inductor L and a switch 1gQ are connected in series to both ends of the inductor, and a light emitting electron tube 1 is connected in parallel to the inductor. However, the light-emitting electron tube 1 is connected so that the thermionic-emitting cathode 3 is on the positive electrode side of the DC power source E. Note that in order to supply current to and heat the thermionic emission type cathode 3, a resistor R is connected in series to both ends of the DC power source E.
, R2 is connected to one end of the thermionic emission type cathode 3, and the other end is connected to the positive electrode of the DC power source E.

In this embodiment, when the switch element Q is turned on (the control signal shown in FIG. However, the current shown in Figure 2 (b) flows.
When the switch element Q is turned on, the light-emitting electron tube 1 has a second
As shown in Figure (c), no current flows), and at this time energy is stored in the inductor. Here, the reason why current does not flow through the light emitting electron tube 1 when the switch element Q is turned on is because the current flows from the anode 4 to the cathode 3 in the light emitting electron tube 1, but no current flows from the cathode 3 to the anode 4. This is because it has a rectifying effect. Then, when the switch element Q is turned off, a current flows through the light emitting electron tube 1 as shown in FIG. 2(C) using the energy stored in this inductor as a power source. Furthermore, at this time, the
DC power supply E, parallel circuit of cathode 3 and resistor R2, resistor R
The cathode 3 is heated to a state where it can be started by the T4 flow flowing in the closed loop of 2, and the light-emitting electron tube 1 is turned on by turning the switch element Q on and off as described above. In this embodiment as well, desired power can be supplied to the light-emitting electron tube 1 by appropriately setting the frequency and on-duty of the control signal of the switch element Q, and the inductance value of the inductor L.

By the way, in the above case, the resistors R+ and R2 were provided to heat the cathode 3, but if the cathode 3 is connected in series with the inductor L as shown in FIG. ,,R2 can be omitted.

Effects of the Invention As described above, the present invention connects a series circuit of an on/off controlled switch element and an inductor to a DC power supply, sets the anode to the negative pole side of the DC power supply, and connects a light-emitting electron tube in parallel to the inductor. It is equipped with a heating means that heats the cathode to a level where discharge can start when a voltage is applied between the anode and cathode in the direction in which current flows from the anode to the cathode, increasing the size and cost. - The light-emitting electron tube itself has the function of a diode, which was a factor in deteriorating efficiency, and the diode can be omitted5.Therefore, it has the advantage of being compact, lightweight, low cost, and highly efficient.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a discharge lamp lighting device as an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation as above, Fig. 3 is a circuit diagram of another embodiment, and Fig. 4 is a diagram of a light emitting electron tube. The schematic configuration diagram, FIG. 5, and FIG. 6 are circuit diagrams of a conventional discharge lamp lighting device, respectively. 1 is a light emitting electron tube, 2 is a tube body, 3 is a cathode, 4 is an anode, L is an inductor, Q is a switch element, E is a DC power supply, and R, , R, are resistors. Figure 3

Claims (1)

[Claims] (1) A thermionic-emitting cathode and an anode are provided in the tube, and electrons emitted from the cathode are accelerated by an electric field caused by a voltage applied between the anode and the cathode, and are converted into a light-emitting gas sealed in the tube. A radiation source that lights up a light-emitting electron tube that has a rectifying effect, in which the light-emitting gas is ionized and excited by collision, causing ultraviolet radiation and emitting light, and current flows from the anode to the cathode, but no current flows from the cathode to the anode. A light lighting device in which a series circuit of a switching element and an inductor to be controlled on and off is connected to a DC power supply, and a light emitting electron tube is connected in parallel to the inductor with the anode on the negative pole side of the DC power supply, and the circuit is connected from the anode to the cathode. 1. A discharge lamp lighting device comprising heating means for heating the cathode to a level at which discharge can be started when a voltage is applied between the anode and the cathode in the direction in which current flows.