JPH04324285A - Luminous radiation electron tube lighting device - Google Patents

Abstract

PURPOSE:To provide smallness in size, lightness in weight, low cost and high efficiency while preventing a lamp life from decreasing and shortening and a lumen maintenance factor from decreasing due to generation of a red heat part by suppressing red heat of a cathode. CONSTITUTION:DC power supplies E1, E2 are connected to an anode 1 and to terminals 2a, 2b in both ends of a cathode 2, in a luminous radiation electron tube G. The power supply is set to a relation where E1not equal to E2 about suppressing red heat. A discharge current I of the luminous radiation electron tube G is obtained by a sum(I=I1+I2) of a discharge current I1 supplied from the DC power supply E1 and a discharge current I2 supplied from the DC power supply E2. A potential difference E(=E2-E1) is applied to the both ends of the cathode 2, and a current If(= E/Rf), determined by a resistance component Rf of the cathode 2, flows in the cathode 2 heated to a temperature necessary during lighting.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting electron tube lighting device for lighting a light-emitting electron tube in which a light-emitting gas sealed within the tube is excited by collisions of accelerated electrons to emit light.

0002

2. Description of the Related Art Conventionally, a light-emitting electron tube is known as disclosed in Japanese Patent Application Laid-Open No. 57-130364. A schematic configuration diagram of the light emitting electron tube is shown in FIG. The light-emitting electron tube G includes a light-transmitting tube body 3 in which a low-pressure light-emitting gas is sealed, a thermionic-emitting cathode 2 disposed within the tube body 3, and an anode 1. It is configured.

This light-emitting electron tube G does not have the inside of the tube body 3 in a complete vacuum state, but in a low vacuum state in which a light-emitting gas such as mercury vapor exists at a pressure of about several mTorr. Then, the electrons emitted from the thermionic emission cathode 2 are accelerated by an electric field caused by an electron acceleration voltage applied between the cathode 2 and anode 1, and the accelerated electrons collide with a light-emitting gas such as mercury vapor. By letting
It is designed to ionize and excite mercury and other substances to cause ultraviolet radiation.

On the other hand, the inner surface of the tube body 3 is coated with an ultraviolet-excited phosphor that converts ultraviolet rays into visible light; this phosphor converts ultraviolet rays into visible light;
Desired visible light can be obtained through the translucent tube 3. This light-emitting electron tube is attracting attention as a compact, lightweight, low-cost, and highly efficient lamp. An example of a lighting device for this light emitting electron tube is a lighting device as shown in FIG. 7 (Japanese Patent Application No. 405553/1999). This lighting device includes a first DC power source E1 and a second DC power source E2.
and an AC power source E3.

First, the positive electrode of the first DC power source E1 is connected to the anode 1 of the light emitting electron tube G, and the negative electrode of the DC power source E1 is connected to one terminal 2a of the cathode 2 of the light emitting electron tube G. It forms a closed loop. Further, the positive electrode of the second DC power source E2 is connected to the anode 1 of the light emitting electron tube G, and the negative electrode of the DC power source E2 is connected to the other terminal 2b of the cathode 2 of the light emitting electron tube G to form a second closed loop. It consists of

Furthermore, the AC power source E3 is connected to one of the transformers T.
The secondary side of the transformer T, the capacitor C, and the cathode 2 are connected in series to form a third closed loop. Note that the DC power supplies E1 and E2 have the same potential. Next, the operation in FIG. 7 will be explained. The discharge current I of the light emitting electron tube G is obtained by the sum of the discharge current I1 supplied from the DC power supply E1 and the discharge current I2 supplied from the DC power supply E2, that is, I=I1 +I2. Since DC power sources E1 and E2 have the same potential, I
1 = I2 = I/2.

Furthermore, since a capacitor C for blocking direct current is connected in series to the secondary side of the transformer T,
The discharge current I1 flows only through the terminal 2a from the anode 1 through the cathode 2, and the discharge current I2 flows only through the terminal 2b from the anode 1 through the cathode 2. In this lighting device, the constant heating current If from the AC power source E3 is as shown in Figure 8.
When the polarity is , a current of I1 -If flows near point A, and I2 +If (=I/2+If) near point B.
current flows. When the constant heating current If has the polarity shown in FIG. 9, I1 +If (=I/2+If) near point A.
The current flows, and near point B, I2 -If (=I/2+
A current If) flows.

That is, in this lighting device, the cathode 2
The degree of addition of the discharge current I and the constant heating current If is small. Therefore, generation of red-hot areas can be suppressed. Furthermore, by adding the diodes in parentheses in FIG. 7, stable operation can be obtained even when there is a potential difference between the DC power sources E1 and E2. Further, the discharge currents I1 and I2 supplied from the DC power sources E1 and E2 are transmitted from the anode 1 of the light-emitting electron tube G to each terminal 2 at both ends of the cathode via the cathode 2.
a and 2b, respectively, and these discharge currents I1 and I2
Since the constant heating current If on the cathode 2 is set in the opposite direction to either of the two, the current is canceled on the cathode 2 of the light-emitting electron tube G, and red heat of the cathode 2 can be suppressed.

[0009]

[Problems to be Solved by the Invention] In the conventional lighting device shown in FIG. 7, the red heat of the cathode 2 can be suppressed, resulting in a decrease in lamp efficiency due to the generation of red hot parts, a shortening of the lamp life, and a decrease in the retention rate. can be prevented. However, this lighting device is small, lightweight, low cost, and has an AC power source E3 that heats the cathode 2 in addition to the DC power sources E1 and E2 that supply power to the lamps.
There was a problem that it was contrary to high efficiency. In other words, the light-emitting electron tube is attracting attention as a compact, lightweight, low-cost, and highly efficient lamp, but as a matter of course, the light-emitting electron tube lighting device is also required to be small, lightweight, low-cost, and highly efficient.

The present invention has been provided in view of the above-mentioned points, and is capable of suppressing the red heat of the cathode, preventing reduction in lamp life, shortening of lamp life, and reduction in retention maintenance rate due to the generation of red hot parts, and The object of the present invention is to provide a light-emitting electron tube lighting device that is small, lightweight, low cost, and highly efficient.

[0011]

[Means for Solving the Problems] The present invention provides a light-emitting electron tube having a cathode and an anode, a first DC power supply for applying a voltage between the anode and one end of the cathode of the light-emitting electron tube, and a second DC power supply that applies a voltage between the anode and the other end of the cathode; and two closed loops in which two discharge currents supplied from both DC power supplies flow from the anode of the light-emitting electron tube to both ends of the cathode, respectively. ,
It consists of an impedance connected in parallel between both ends of the anode and cathode of the light-emitting electron tube, and the potentials of the two DC power supplies are set to different values to the extent that the cathode does not become red hot, and the potential difference between the two ends of the cathode is A heating current is constantly passed through the cathode.

0012

[Operation] By setting the potentials of both DC power supplies to different values to the extent that the cathode does not become red hot, the discharge current at the cathode and the constant heating current determined by the potential difference between the two ends of the cathode and the resistance of the cathode can be reduced. The degree of addition of Since a heating current is constantly applied to both ends of the cathode, there is no need for a separate power source to constantly heat the cathode, unlike in the past, and the device is small, lightweight, low cost, and highly efficient.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a light-emitting electron tube G having a cathode 2 provided between two terminals 2a and 2b and an anode 1 having one terminal, DC power supplies E1 and E2, and a DC power supply supplied from the DC power supplies E1 and E2. discharge current I1,I
2 can flow from the anode 1 of the light emitting electron tube G to the two terminals 2a and 2b at both ends of the cathode via the cathode 2, one terminal 2a of the anode 1 and the cathode 2, and the other terminal of the anode 1 and the cathode 2. Impedances Z1 and Z2 inserted between terminals 2b of
It is made up of. Furthermore, DC power supplies E1 and E2
is set so that E1≠E2.

The discharge current I of the light-emitting electron tube G in this lighting device is equal to the discharge current I1 supplied from the DC power supply E1.
and the discharge current I2 supplied from the DC power source E2, that is, I=I1 +I2. Furthermore, since the DC power sources E1 and E2 are set as E1 ≠ E2, the potential difference ΔE (=E2 - E1)
is applied to both ends of the cathode 2, a current If (=ΔE/Rf) determined by the resistance Rf of the cathode 2 flows through the cathode 2, and the cathode 2 is heated to a required temperature during lighting.

Further, the potential difference ΔE mentioned above is such that the current If determined by the resistance Rf of the cathode 2 is equal to the discharge current I1.
, I2, If, that is, the potential difference ΔE between the DC power supplies E1 and E2, is set to such an extent that the generation of red heat at the cathode 2 is suppressed. Next, a specific example is shown in FIG. A closed loop consisting of a series circuit of the DC power supply E, the primary side of the transformer T1, and the switching element Q1, the first winding n1 on the secondary side of the transformer T1, and the diode D.
1, a closed loop consisting of a series connection of a parallel circuit of a capacitor C2, an anode 1 and a terminal 2b of a cathode 2 of a light emitting electron tube G, and a second winding n on the secondary side of a transformer T1.
2, a closed loop consisting of a series connection of a diode D2, a capacitor C3, and a parallel circuit of terminals 2a of the anode 1 and cathode 2 of the light-emitting electron tube G, and a control circuit S for controlling the switching element Q1. In addition, the winding n1 and the winding n2 on the secondary side of the transformer T1
The number of turns is different.

The DC power source E is obtained by full-wave rectifying the commercial AC power source Vs with a diode bridge DB and smoothing it with a capacitor C1. By turning on and off the switching element Q1, a rectangular wave voltage is applied to the primary side of the transformer T1, and thereby a rectangular wave voltage is induced in the winding n1 and the winding n2 on the secondary side of the transformer T1. is charged to capacitors C1 and C2 via diodes D1 and D2.

[0017] A winding n1 on the secondary side of the transformer T1;
Since the number of turns of winding n2 is different, capacitor C2
, C3 have a potential difference ΔE between the voltages E1 and E2 across the terminals. The discharge current I is the voltage E1 across the capacitor C2.
The discharge current I1 supplied from the capacitor C3
The sum of the discharge current I2 supplied from the voltage E2 across the
That is, it is obtained by I=I1+I2.

Furthermore, the DC power supplies E1 and E2 are connected to E1
By setting ≠E2, the potential difference △E is applied across the cathode 2, and a current If (=△E/Rf) determined by the resistance Rf of the cathode 2 flows to the cathode 2, which increases the temperature required during lighting. Cathode 2 is heated to (Example 2) As shown in FIG. 3, a closed loop consisting of a series connection of a DC power supply E, the primary side of a transformer T1, a switching element Q1, a secondary side of the transformer T1, a diode D1, and a capacitor C2 and light emitting electron tube G
A closed loop consisting of a series connection of the parallel circuit of the anode 1 and one terminal 2a of the cathode 2, a closed loop consisting of the series connection of the DC power supply E, the primary side of the transformer T2, and the switching element Q2, and the two of the transformer T2. A closed loop consisting of a series connection of a parallel circuit of the next side, diode D2, capacitor C3, and the other terminal 2b of the anode 1 and cathode 2 of the light-emitting electron tube G, and the switching element Q1.
, Q2.

By appropriately setting the control signals of the switching elements Q1 and Q2, the capacitors C2 and C
The voltages E1 and E2 across the two terminals are set such that E1≠E2. (Example 3) Example 3 is shown in FIG. In this embodiment, negative output 3-terminal power supply regulators IC1 and IC2 are used,
The power regulators IC1 and IC2 are of the AN7900 series manufactured by Matsushita Electronics Industries, Ltd. The ■ pins of the power supply regulators IC1 and IC2 are input terminals, the ■ pins are common terminals, and the ■ pins are output terminals.

Different voltages E1 and E2 are applied to both ends of capacitors C1 and C2 from a DC power supply E using negative output three-terminal power supply regulators IC1 and IC2 with different outputs.
(E1 ≠ E2) is generated. Capacitor C1,
The positive potential side of C2 is the anode 1 of the light emitting electron tube G.
It is connected to the. The negative side of the capacitor C1 is connected to one terminal 2a of the cathode 2 of the light emitting electron tube G, and the negative side of the capacitor C2 is connected to the other terminal 2b of the cathode 2 of the light emitting electron tube G.

By the way, in the present invention in each embodiment, if the potential difference ΔE between the first DC power source E1 and the second DC power source E2 is increased, it can be used for preliminary preheating at the time of starting. That is, as shown in FIG.
Insert the switching element Q1 into the line connecting the positive side intersection of 1 and E2 and the anode 1 of the light emitting electron tube G,
By turning off only during preliminary preheating, preliminary preheating can be performed without applying voltage to the light-emitting electron tube G.

Furthermore, without fixing the magnitude relationship between the voltage values of the DC power sources E1 and E2, E1 > E2 and E2 < E
1 alternately, the constant heating current flowing to the cathode of the light-emitting electron tube can be reversed, and the effect of suppressing the generation of red heat on the cathode becomes greater. Furthermore, by controlling the potential difference ΔE, the heating current can be adjusted at all times, and appropriate cathode heating can be performed at all times.

[0023]

As described above, the present invention provides a light-emitting electron tube having a cathode and an anode, a first DC power supply that applies a voltage between the anode and one end of the cathode of the light-emitting electron tube, and a second DC power supply that applies a voltage between the anode and the other end of the cathode; and two closed loops in which two discharge currents supplied from both DC power supplies flow from the anode of the light-emitting electron tube to both ends of the cathode, respectively. , consists of an impedance connected in parallel between both ends of the anode and cathode of the light emitting electron tube, and the potentials of the two DC power supplies are set to different values to the extent that the cathode does not become red hot, and the potential difference between the two ends of the cathode is By setting the potentials of both DC power supplies to different values to the extent that the cathode does not become red hot, the discharge current at the cathode and the voltage at both ends of the cathode are controlled. The degree of addition of the constant heating current determined by the potential difference and the cathode resistance is reduced, suppressing the generation of red-hot areas on the cathode, reducing lamp efficiency, shortening lamp life, and reducing the locking maintenance rate due to the generation of red-hot areas. In addition, since the potential difference between the two DC power supplies is applied to both ends of the cathode and a constant heating current is obtained, there is no need for a separate power supply to constantly heat the cathode. First, it has the effect of realizing small size, light weight, low cost, and high efficiency.

Furthermore, by reversing the magnitude relationship between the values of both DC power supplies, the effect of suppressing the generation of red heat on the cathode is increased. Furthermore, by controlling the potential difference between the two DC power supplies, for example, by increasing the potential difference between the two DC power supplies, it can be used for advance preheating at the time of starting.

[Brief explanation of drawings]

FIG. 1 is a basic circuit diagram of an embodiment of the present invention.

FIG. 2 is a circuit diagram of a specific embodiment.

FIG. 3 is a specific circuit diagram of Example 2.

FIG. 4 is a specific circuit diagram of Example 3.

FIG. 5 is an explanatory circuit diagram when performing advance preheating.

FIG. 6 is a perspective view of a light emitting electron tube.

FIG. 7 is a circuit diagram of a conventional example.

FIG. 8 is an explanatory diagram of discharge current operation.

FIG. 9 is an explanatory diagram of discharge current operation.

[Explanation of symbols]

1 Anode 2 Cathode G Light emitting electron tube E1 First DC power supply E2 Second DC power supply I1 Discharge current I2 Discharge current Z1 Impedance Z2 Impedance If Constant heating current

Claims (3)

[Claims] Claim 1: A light-emitting electron tube having a cathode and an anode, a first DC power supply for applying a voltage between one end of the anode and the cathode of the light-emitting electron tube, and the other end of the anode and cathode of the light-emitting electron tube. the second to apply a voltage between
A DC power supply, two closed loops in which two discharge currents supplied from both DC power supplies flow from the anode to the cathode of the light-emitting electron tube, respectively, are connected in parallel between the anode and cathode ends of the light-emission electron tube, respectively. The electric potential of the two DC power supplies is set to different values to the extent that the cathode does not become red hot, and the heating current is constantly passed through the cathode due to the potential difference between the two ends of the cathode. A light emitting electron tube lighting device. 2. The light-emitting electron tube lighting device according to claim 1, wherein the magnitude relationship between the values of both DC power supplies is reversed. 3. The light-emitting electron tube lighting device according to claim 1, further comprising means for controlling the potential difference between the two DC power supplies.