JPH04324295A - Light radiation electron tube lighting device - Google Patents

Abstract

PURPOSE:To maintain a condition of lighting a light radiation electron tube even at a low ambient temperature and a small optical output. CONSTITUTION:In a lighting power feed source 2, an electron emitted from a filament 1b is accelerated by applying accelerating voltage between the filament 1b and an accelerating electrode 1c. Power is fed to the filament 1b by a filament heating circuit 3. The filament heating circuit 3 can adjust a conduction current to the filament 1b independently of the lighting power feed source 2 to control tube power by adjusting the conduction current.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is characterized in that a filament serving as a cathode and an accelerating electrode that accelerates electrons emitted from the filament are placed inside a bulb filled with a light-emitting gas that emits light when excited by the collision of the accelerated electrons. This invention relates to a light-emitting electron tube lighting device for lighting a light-emitting electron tube placed opposite to the light-emitting electron tube.

0002

2. Description of the Related Art Conventionally, a light emitting electron tube 1 having a structure as shown in FIG.
30364). The light-emitting electron tube 1 includes a filament 1b that serves as a thermionic-emitting cathode, and an accelerating electrode 1c that accelerates electrons emitted from the filament 1b, in a bulb 1 made of a transparent material such as glass. It has a configuration in which the two are placed opposite each other. The interior of the bulb 1a is filled with a mixed gas of a light emitting gas such as mercury vapor and neon, which is a rare gas, at a pressure of about several milliTorr, resulting in a low vacuum. Further, the inner peripheral surface of the bulb 1a is coated with a phosphor (not shown) that converts ultraviolet rays into visible light.

In order to light up the light emitting electron tube 1, electrons are emitted by supplying power between both ends of the filament 1b, and the filament 1b and the accelerating electrode are connected so that the filament 1b becomes the negative electrode and the accelerating electrode 1c becomes the positive electrode. Electrons are accelerated by applying an accelerating voltage between the electrode and the electrode 1c. Accelerated electrons ionize or excite gas atoms and molecules sealed in the bulb 1a by colliding with them, and if the light emitting gas is mercury vapor, mainly ultraviolet rays are emitted. become. This ultraviolet light is converted into visible light by the phosphor, and visible light is emitted from the bulb 1a. This light emitting electron tube 1
has the advantages of small size, light weight, low cost, and high efficiency.
Demand is expected to increase in the future.

By the way, as a light-emitting electron tube lighting device, the configuration shown in FIG. 10 has been considered. This light emitting electron tube lighting device has a DC power source E. A series circuit of a switching element Qa and an inductor L is connected between both ends of the DC power supply E. Further, one end of the parallel circuit of the switching element Qb and the capacitor Cb is connected to the connection point between the switching element Qa and one end of the inductor L via the diode D, and the other end of the parallel circuit is connected to the filament of the light-emitting electron tube 1. It is connected to the other end of the inductor L via 1b. Further, the acceleration electrode 1c of the light emitting electron tube 1 is connected to the connection point between the diode D and the switching element Qb. Each switching element Qa, Qb is controlled on/off by a control circuit S. The DC power source E is obtained by rectifying the AC power source AC (for example, obtained by stepping down a commercial AC power source) with a bridge rectifier RE made up of a diode bridge, and then smoothing it with a capacitor Ca.

In this light-emitting electron tube lighting device, before lighting the light-emitting electron tube 1 by applying an accelerating voltage between the filament 1b and the accelerating electrode 1c, the filament 1b is first preheated. That is, the switching element Qa is turned on and off while the switching element Qb is turned on. During the period when the switching element Qa is on, the current from the DC power supply E flows through the inductor L, and energy is accumulated in the inductor L, and during the period when the switching element Qb is off, the energy accumulated in the inductor L causes the current to flow through the inductor L. , a current flows through the path of diode D, switching element Qb, and filament 1b, and the filament 1b is heated. After the filament 1b is heated to a temperature at which the light-emitting electron tube 1 can be lit by such preheating, the switching element Qa is controlled to be turned on and off while the switching element Qb is turned off. At this time, the alternating current component of the current passing through the diode D flows to the filament 1b through the capacitor Cb, so the filament 1b is constantly heated, and the direct current component causes the filament 1b and the accelerating electrode 1 to be heated.
Since an accelerating voltage is applied between the light emitting electron tube 1 and
lights up.

[0006]

[Problems to be Solved by the Invention] As is clear from the above configuration, when the light-emitting electron tube 1 is lit, the on-duty and switching frequency when turning on and off the switching element Qa are changed by the control circuit S. By doing so, the amount of energy supplied to the light emitting electron tube 1 changes, so that the light output from the light emitting electron tube 1 can be changed to perform dimming.

However, in the above configuration, by reducing the on-duty of the switching element Qa, the filament 1b of the light-emitting electron tube 1 and the accelerating electrode 1c are
When the light output is reduced by reducing the tube current flowing between the filament 1b and the filament 1b, the heating current flowing through the filament 1b also decreases, thereby reducing the amount of electrons emitted. As a result, a problem arises in that the lighting state cannot be maintained. Further, even when the ambient temperature is low, the temperature of the filament 2 cannot be increased, so the amount of electrons emitted from the filament 2 decreases, causing a problem that the lighting state cannot be maintained.

[0008] The present invention aims to solve the above-mentioned problems, and aims to ensure a heating current to the filament independently of the accelerating voltage, and to always emit a sufficient amount of electrons from the filament. Accordingly, it is an object of the present invention to provide a light-emitting electron tube lighting device that can maintain the lighting state of the light-emitting electron tube even when the light output is low or the ambient temperature is low.

[0009]

[Means for Solving the Problems] In order to achieve the above object, in the invention of claim 1, a filament serving as a cathode and an accelerating electrode for accelerating electrons emitted from the filament are arranged so that collision of accelerated electrons causes In a light-emitting electron tube lighting device that lights a light-emitting electron tube placed oppositely in a bulb filled with a light-emitting gas that emits light when excited, an acceleration device that accelerates electrons emitted from the filament is placed between a filament and an acceleration electrode. It is equipped with a lighting power supply means for applying a voltage, and a filament heating means for controlling the tube power by adjusting the current flowing to the filament.

In the second aspect of the invention, the filament heating means blinks the light-emitting electron tube by switching the current applied to the filament in two levels, large and small.

[0011]

[Function] According to the structure of claim 1, the tube power is controlled by controlling the current flowing to the filament, and it is possible to reduce the light output during dimming or when the ambient temperature is low. , a sufficient amount of electrons are emitted from the filament to maintain the lighting state.

According to the second aspect of the present invention, by switching the electric current to the filament into two levels, large and small, the tube power of the light-emitting electron tube is switched into two levels, thereby causing the light-emitting electron tube to blink.

[0013]

【Example】

(Example 1) As shown in FIG. 1, for the light emitting electron tube 1 shown in FIG. A power supply 2 and a filament heating circuit 3, which is filament heating means for supplying heating power between both ends of the filament 1b, are provided. The output of the lighting power source 2 is a constant voltage direct current, and the acceleration voltage is applied by connecting the filament 1b to the negative electrode and the acceleration electrode 1c to the positive electrode. Further, the filament heating circuit 3 is configured to be able to adjust the current applied to the filament 1b.

FIG. 2 shows a specific circuit corresponding to FIG. 1. The filament heating circuit 3 is an integrated circuit IC1 for a switching regulator (for example, μPC4 manufactured by NEC).
94) as the main components, and the 8th terminal and 1st
A square wave is output from terminal 1. The frequency of the rectangular wave is determined by the capacitor C1 and the resistor R1, and the on-duty can be controlled in the range of 0 to 100%. The output of the 8th terminal and the 11th terminal is an inverting circuit IC2 (for example, μPC4 manufactured by NEC).
049), the signal is inverted and the waveform is shaped, and the switching element Q1, which is a MOSFET, is controlled to turn on and off. The switching element Q1 is connected in series with the primary winding of the heating transformer T1 via a diode D1, and this series circuit is connected across the DC power supply DC. Further, a capacitor C2 is connected in parallel to the primary winding of the heating transformer T1.

When the switching element Q1 is turned on, current flows through the primary winding of the heating transformer T1 and at the same time the capacitor C2 is charged, and when the switching element Q1 is turned off, the energy stored in the primary winding is released. At the same time, the charge accumulated in the capacitor C2 is released. Therefore, 2 of heating transformer T1
An alternating current voltage is induced in the next winding. That is, heating transformer T1, switching element Q1, diode D1
, and capacitor C2 constitute an inverter circuit consisting of a single-stone inverter circuit, and the output of the inverter circuit is controlled by the output of a control circuit whose main components are an integrated circuit IC1 and an inverting circuit IC2. Here, the longer the on-time of the switching element Q1, the greater the output power from the secondary winding of the heating transformer T1. The secondary winding of the heating transformer T1 is
It is connected to the filament 1b via a coupling transformer T2. The secondary winding of the coupling transformer T2 has a center tap, to which the negative pole of the lighting power supply 2 is connected via a current detection resistor R0.

By the way, in the integrated circuit IC1, a reference voltage of 5V is output from the reference terminal, which is the 14th terminal, and is detected from the connection point between the center tap of the secondary winding of the coupling transformer T2 and the current detection resistor R0. By inputting the voltage divided by the variable resistor VR to the 2nd terminal and the reference voltage to the 1st terminal, the 1
The on-duty of the output signal is controlled according to the difference in input voltage between the No. 1 terminal and the No. 2 terminal. That is, variable resistor VR
The voltage divided by is higher than the reference voltage, and the larger the difference, the smaller the on-duty of the rectangular wave output from the integrated circuit IC1. integrated circuit IC1
Since the rectangular wave output from the inverter IC2 is inverted by the inverting circuit IC2, the higher the tube voltage, the lower the terminal voltage of the current detection resistor R0, which causes the switching element Q1 to be inverted.
The on-time of the filament 1b becomes longer, and as a result, the current flowing to the filament 1b increases. Since the voltage detected by the current detection resistor R0 corresponds to the current flowing between the filament 1b and the accelerating electrode 1c of the light-emitting electron tube 1, that is, the tube current, when the tube current increases (i.e.,
When the tube voltage decreases), the current flowing to the filament 1b decreases.

Here, a variable resistor V is used for dimming.
When the current flowing to the filament 1b is increased by adjusting R, the tube voltage, which is the voltage between the filament 1b and the accelerating electrode 1c, decreases, and the output voltage of the lighting power source 2 is a constant voltage. This results in an increase in tube current. That is, the tube current increases or decreases as the current flowing to the filament 1b increases or decreases. Therefore, if the tube current is detected by the tube current detection resistor R0 and feedback control is performed to increase or decrease the current flowing to the filament 1b in accordance with the increase or decrease in the tube current, the tube current can be kept almost constant, and the lamp will turn on. The situation becomes stable. The reference voltage is connected to the 4th terminal of the integrated circuit IC1 through resistors R2 and R
A voltage divided by 3 is applied to the integrated circuit IC1.
By limiting the lower limit of the on-duty of the rectangular wave output from the filament 1b, the current flowing to the filament 1b is prevented from becoming excessive.

In this embodiment, the tube current is detected by the current detection resistor R0, but it is also configured to detect the tube current by using a current transformer instead of the current detection resistor R0. Good too. (Embodiment 2) In this embodiment, as shown in FIG. 3, the main part of the lighting power source 2 is constructed by a half-bridge type inverter circuit.

That is, an AC power source A such as a commercial AC power source
A DC voltage is obtained by full-wave rectifying C through a power switch SW by a bridge rectifier RE1 made of a diode bridge, and then smoothing by a capacitor C5. A series circuit between the collectors and emitters of a pair of transistors Q2 and Q3, which serve as switching elements, is connected between both ends of the capacitor C5, and diodes D2 and D3 are connected in antiparallel between the collectors and emitters of each transistor Q2 and Q3. Connected. Moreover, between the collector and emitter of one transistor Q2,
A series circuit of capacitor C6 - primary winding of output transformer T3 - inductor L1 - primary winding of feedback transformer T4 is connected, and capacitor C7 is connected in parallel to the primary winding of output transformer T3. Feedback transformer T4
has a pair of secondary windings, each connected to each transistor Q2.
, Q3 is connected between the base and emitter of. Each secondary winding is wound so that the polarity is opposite to each other, and the current induced in one of the secondary windings is connected to the corresponding transistor Q2,
When transistor Q3 is forward biased, the other transistors Q2 and Q3 are reverse biased. A resistor R is connected to the base of the transistor Q3.
5 and a capacitor C8, one end of a trigger element (DIAC) Q4 that constitutes a starting circuit is connected.

According to this configuration, when the power is turned on, the trigger signal is output from the starting circuit and the transistor Q2 is activated.
is turned on, capacitor C6 - output transformer T3
The primary winding of and capacitor C7 - inductor L1
- Primary winding of feedback transformer T4 - Transistor Q2
Current flows through this path, and from then on, as is well known, both transistors Q2 and Q3 are activated by the action of the feedback transformer T4.
The oscillation operation is performed so that the oscillators are alternately and selectively turned on. Here, the oscillation frequency is set to several tens of kHz. The secondary winding of the output transformer T3 has a center tap, and the high frequency induced in the output transformer T3 is
Full-wave rectification is performed by diodes D4 and D5. After rectification, the voltage is smoothed by a capacitor C9, and the voltage across the capacitor C9 is applied to the light-emitting electron tube 1 as an accelerating voltage.

On the other hand, the voltage across capacitor C5 is applied to the series circuit of resistor R6 and capacitor C10,
The filament heating circuit 3 is powered by the voltage across the capacitor C10. In Example 1, the current detection resistor R0
The voltage across the capacitor C10 is divided by the variable resistor VR and compared with the reference voltage. However, in this embodiment, the voltage across the capacitor C10 is divided by the resistor R7 and the variable resistor VR. Compare the voltage to a reference voltage. Here, the voltage across the capacitor C10 decreases as the tube voltage increases, so if the tube voltage increases, the integrated circuit I
The on-duty of the rectangular wave output from C1 increases. Also, the output of the integrated circuit IC1 is not an inverting circuit but a buffer IC3 (for example, μPC4 manufactured by NEC).
050) to control the switching element Q1. Therefore, when the tube voltage increases, the on-duty of the rectangular wave output from the integrated circuit IC1 increases, and the current flowing to the filament 1b increases. Furthermore, for dimming, if the on-duty of the rectangular wave output from the integrated circuit IC1 is reduced by adjusting the variable resistor VR, the tube current of the light-emitting electron tube 1 is reduced, and the light output is reduced. It is possible to do so.

In this embodiment, since the tube voltage increases as the tube current decreases, the rare gas sealed in the bulb 1a emits light. For example, if the rare gas is neon, a red luminescent color can be obtained. Therefore, when the tube current is adjusted to reduce the light output, the emitted light color changes at the same time, and dimming and color adjustment are performed at the same time.
Become. The other configurations and operations are the same as those in the first embodiment, so their explanations will be omitted.

(Third Embodiment) In this embodiment, as shown in FIG. 4, an astable multivibrator 3a is added to the filament heating circuit 3 in the second embodiment. The astable multivibrator 2a is a general-purpose timer integrated circuit IC4 (for example, μPD5555 manufactured by NEC).
It consists of additional peripheral parts. Also, integrated circuit IC
1, the voltage to be compared with the reference voltage is a voltage obtained by dividing the output voltage of the No. 3 terminal of the astable multivibrator 3a by the resistor R8 and the variable resistor VR.

Therefore, astable multivibrator 3
When the output of a is at the L level (see FIG. 5(a)), the on-duty of the switching element Q1 becomes very small, and almost no current flows through the filament 1b (see FIG. 5(b)). As a result, the light emitting electron tube 1 is turned off. On the other hand, when the output of the astable multivibrator 3a is at H level (see FIG. 5(a)), the on-duty of the switching element Q1 becomes the magnitude set by the variable resistor VR (see FIG. 5(b)). ), the current passing through the filament 1b increases compared to the case where the output of the No. 3 terminal of the astable multivibrator 3a is at L level. At this time, filament 1b
Since the amount of electrons emitted from the tube increases and the tube voltage decreases, when the tube voltage falls below the voltage across the capacitor C9, the light-emitting electron tube 1 lights up. Here, the oscillation frequency of the astable multivibrator 3a is set to several tens of Hz or less, and the light-emitting electron tube 1 blinks at this frequency. In FIG. 5, the current is flowing through the filament 1b even when the light emitting electron tube 1 is off, but the current flowing through the filament 1b is completely zero.
You can also do this. The other configurations and operations are the same as those in the second embodiment, so their explanations will be omitted.

(Embodiment 4) In this embodiment, as shown in FIG. 6, an example is shown in which a plurality of light emitting electron tubes 1 are connected in series. In this case, the acceleration voltage of each light emitting electron tube 1 is set to V
If n light-emitting electron tubes 1 are connected in series, the output voltage of the lighting power supply 2 is required to be n×Va. In this way, it is possible to connect a plurality of light emitting electron tubes 1 in series and light them.

(Embodiment 5) In this embodiment, a light emitting electron tube 1
As shown in FIG. 7, the lighting power source 2 shown in Embodiment 2 is used, and a secondary winding is provided in the inductor L1. The filament 1b is heated by the induced output. One end of the filament 1b is connected to the negative electrode of a storage battery B that serves as a power source during a power outage, and the positive electrode of the storage battery B is connected to the acceleration electrode 1c of the light-emitting electron tube 1 via an emergency switch SW1 that is turned on during a power outage. It is connected.

Therefore, under normal conditions, when the emergency switch SW1 is off, an accelerating voltage is applied by the lighting power source 2, and the filament 1
The light-emitting electron tube 1 is turned on by being energized by the light emitting electron tube 1. Additionally, in the event of a power outage, emergency switch SW1 is turned on.
Accelerating voltage is applied by the storage battery B, and current is supplied to the filament 1b through the secondary winding of the inductor L1 to maintain the lighting state.

(Embodiment 6) In this embodiment, as shown in FIG. 8, the lighting supply power source 2 is an AC power source. In this configuration, the light emitting electron tube 1 is activated only at half-wave of the AC power source. lights up. Other configurations and operations are similar to those in the first embodiment.

[0029]

As described above, according to the structure of claim 1, by controlling the current flowing to the filament,
It controls the tube power, and has the advantage of being able to reduce the light output when dimming, and maintain the lighting state by ensuring sufficient tube current even when the ambient temperature is low. .

According to the second aspect of the present invention, by switching the electric power supplied to the filament in two stages, large and small, the tube current of the light-emitting electron tube can be switched in two stages, thereby producing the effect of blinking the light-emitting electron tube.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a circuit diagram showing a second embodiment.

FIG. 3 is a circuit diagram showing a third embodiment.

FIG. 4 is a circuit diagram showing a fourth embodiment.

FIG. 5 is an explanatory diagram of the operation of the fourth embodiment.

FIG. 6 is a schematic configuration diagram showing a fifth embodiment.

FIG. 7 is a circuit diagram showing a sixth embodiment.

FIG. 8 is a block diagram showing a seventh embodiment.

FIG. 9 is a perspective view showing a light-emitting electron tube according to the present invention.

FIG. 10 is a circuit diagram showing a conventional example.

[Explanation of symbols]

1. Light-emitting electron tube 1a Valve 1b Filament 1c Acceleration electrode 2 Power supply for lighting 3 Filament heating circuit

Claims (2)

[Claims] Claim 1: A light emitting device in which a filament serving as a cathode and an acceleration electrode that accelerates electrons emitted from the filament are placed opposite each other in a bulb filled with a light emitting gas that emits light when excited by collisions with the accelerated electrons. In a light emitting electron tube lighting device for lighting an electron tube, a lighting power supply means for applying an acceleration voltage between a filament and an acceleration electrode to accelerate electrons emitted from the filament, and adjusting a current flowing to the filament. A light emitting electron tube lighting device comprising: filament heating means for controlling tube power. 2. The light-emitting electron tube lighting device according to claim 1, wherein the filament heating means blinks the light-emitting electron tube by switching the current applied to the filament in two levels, large and small.