JPH05144586A - Optical emission electronic tube lighting device - Google Patents

Abstract

PURPOSE:To prevent the breakage of a lighting device or bad effects to a lamp due to abnormally large flow of a lamp current by controlling to prevent the flow of the lamp current of a specified value or more by using the lamp itself for a main current limiting element. CONSTITUTION:A optical emission electronic tube 2 is lighted by a constant voltage power supply 1, a lamp current is detected by a current detection circuit 3, and it is compared with a diamming signal by a preheating circuit to control filament heating powre for lighting the electronic tube 2 stably. An output current circuit 5 and an output current specifying circuit 6 are added to the power supply 1, so the circuit 6 operates when the lamp current is increasing abnormally, thereby the lamp current is regulated not to exceed a predetermined value.

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 which emits light by exciting a light-emitting gas enclosed in the tube by collision of accelerated electrons to emit light and capable of dimming to a low luminous flux. The present invention relates to a radiant electron tube lighting device.

[0002]

2. Description of the Related Art Conventionally, a light emitting electron tube as disclosed in Japanese Patent Laid-Open No. 57-130364 is known.
Various lighting devices for lighting the light emitting electron tube have been proposed, but these can be roughly classified into the following two types.

(A) A lighting device having a current limiting element. These have the same structure as the conventional discharge lamp ballast, and as shown in FIG.
As shown in FIG. 10, the commercial lighting device for commercial lighting 2 of the commercial power source 13 and the high frequency power from the high frequency power source 14 are current-limited by the current limiting element 11 and are stepped down by the step-down transformer 13, and the light emitting electron tube 12 is driven to a high frequency. There are a high-frequency lighting device for lighting, a DC lighting device for rectifying the output of the step-down transformer 13 by the rectifying elements 15 and 16 and smoothing it by the capacitor 17, and lighting the light emitting electron tube 12 by direct current as shown in FIG. ..

(B) A lighting device having no current limiting element. Unlike the conventional discharge lamp ballast, this does not have a current limiting element. In this method, the filament impedance of the light emitting electron tube is controlled by controlling the filament heating power, and the lamp itself is used as a current limiting element. FIG. 12 shows a commercial lighting device, in which the filament heating power of the light emitting electron tube 12 is controlled by the preheating circuit 18, the lamp voltage Vx thereof is made substantially equal to the power supply voltage Vs of the commercial power supply 13, and the lamp is stably lit. FIG. 13 shows a DC lighting device, in which the filament heating power of the light emitting electron tube 12 is controlled by the preheating circuit 18, and the lamp voltage is Vx.
Is set to be substantially equal to the power supply voltage Vs of the DC power supply 19 so that the DC light is stably lit. FIG. 14 shows a lamp current detection circuit 20.
Is a DC lighting device provided with a preheating circuit 18 for detecting a lamp current flowing from the DC power supply 19 to the light emitting electron tube 12.
By controlling the lamp heating power and controlling the lamp impedance so that the lamp voltage Vx becomes substantially equal to the power supply voltage Vs of the DC power supply 19. It is also possible to further develop this system and control the preheating power of the light emitting electron tube 12 to dim the light emitting electron tube 12.

[0005]

However, these methods have the following drawbacks. First, FIG.
In the method (a) illustrated in FIGS.
Therefore, there is a drawback that the power loss there increases, the efficiency decreases, and the cost of the apparatus also increases. Next, in the method (b) as illustrated in FIGS. 12 to 14, there is a drawback that the power supply voltage Vs> the lamp voltage Vx due to a decrease in the lamp voltage due to changes with time or changes in the ambient temperature, and the lamp current becomes abnormally large. is there.

No explanation is required for the drawback (a). On the other hand, the drawback of (b) above is due to the proportion of the gas enclosed in the lamp. Gases such as mercury, neon, and argon are enclosed in the lamp, and mercury has the lowest ionization voltage among these gases. Further, among the vapor pressures of these gases, mercury is most easily affected by the ambient temperature and the like. Therefore, when the mercury vapor pressure becomes high due to a change in ambient temperature or the like, the lamp voltage becomes low, and when the mercury vapor pressure becomes low, the lamp voltage becomes high. That is, when the ambient temperature is low, the lamp voltage is high, and when the ambient temperature is high, the lamp voltage is low.

As a device that is less susceptible to such an ambient temperature, there is a device that encloses amalgam so that the mercury vapor pressure is always at an optimum value. However, amalgam has a drawback that it takes time to set the mercury vapor pressure to an optimum value. Therefore, in addition to the amalgam (hereinafter referred to as the main amalgam), there is one in which an auxiliary amalgam is arranged near the filament. As for the rising characteristics of this lamp, after starting, the mercury vapor pressure is low, and thereafter, the mercury vapor pressure becomes high due to the influence of the auxiliary amalgam. And finally, the mercury vapor pressure becomes an appropriate value due to the main amalgam. In other words, the rising characteristics of the lamp voltage are:
Higher, then lower, and eventually to a proper value.

As described above, it is understood that there is a mode in which the lamp voltage changes due to changes in the ambient temperature of the lamp, changes with time in the amalgam-containing lamp, etc., and the lamp current becomes abnormally large.

On the other hand, this type of light emitting electron tube has a characteristic that when the filament heating power is increased, the lamp voltage is lowered, and conversely, when the filament heating power is reduced, the lamp voltage is increased. Therefore, by utilizing this characteristic, it is possible to solve the problem that the lamp voltage fluctuates due to a change in ambient temperature. However, there is a limit in controlling the lamp voltage by this filament heating means. For example, when a large lamp current is passed, the filament is sufficiently heated by itself. Under these conditions, the lamp voltage drops, and to correct it,
Even if the filament heating power is reduced, the limit is when the filament heating power becomes zero. That is, when the filament heating power becomes zero, the lamp voltage becomes the uncontrollable state, the lamp voltage decreases, and the power supply voltage Vs> the lamp voltage Vx, and the lamp current abnormally flows. It was

FIG. 15 shows the relationship between the preheating power Wf, the lamp voltage Vx, and the lamp current Ix when the ambient temperature Ta changes, and FIG. 16 shows the mercury vapor pressure P, the preheating power Wf, and the lamp voltage of the light emitting electron tube containing amalgam. Vx, lamp current Ix
Shows the relationship. Note that the lighting device is normally destroyed where the lamp current exceeds the reference value in FIG. Even if it is not destroyed, it will seriously affect the lamp. Further, as described above, the light emitting electron tube can be dimmed by controlling the preheating power. However, when the preheating power is zero in FIG. Is impossible.

The present invention has been made in view of the above points, and an object of the present invention is to turn on a light emitting electron tube by using the lamp itself as a current limiting element and to cause an abnormally large lamp current. It is to prevent the lighting device from being damaged and the lamp from being adversely affected by the flowing.

[0012]

In order to solve the above problems, the present invention controls the lamp impedance of the light emitting electron tube 2 by controlling the filament heating power as shown in FIG. However, the light emitting electron tube lighting device using the lamp itself as a main current limiting element is provided with a control circuit for controlling the lamp current so that the lamp current does not flow beyond a specified value.

As shown in FIG. 8, by controlling the filament heating power, the lamp impedance of the light emitting electron tube 2 is controlled so that the lamp itself is the main current limiting element and the lamp current is equal to or more than the specified value. The first light emitting electron tube lighting device 7 provided with a control circuit for controlling so as not to flow and the second light emitting electron tube lighting device 8 having a main current limiting element in the circuit are provided to provide the light emitting electron tube 2 When the filament heating power is supplied, the first light emitting electron tube lighting device 7 lights up, and when the filament heating power is not supplied, the second light emitting electron tube lighting device 8 lights up. It is preferable to turn on the light. Also,
Even when dimming the light emitting electron tube 2, dimming is performed by the first light emitting electron tube lighting device 7 when the filament heating power is supplied, and when the filament heating power is not supplied, the second light dimming is performed when the filament heating power is not supplied. It is preferable that the light emitting electron tube lighting device 8 is used for dimming.

[0014]

In the present invention, by controlling the filament heating power, the lamp impedance of the light emitting electron tube 2 is controlled, and in the light emitting electron tube lighting device in which the lamp itself is the main current limiting element, the lamp current is Since the light emitting electron tube 2 can be turned on by using the lamp itself as a current limiting element because it has a control circuit for controlling so that the current does not flow over the specified value, the circuit efficiency can be increased and the device can be downsized. Moreover, it is possible to prevent damage to the lighting device and adverse effects on the lamp due to an abnormally large amount of lamp current flowing. Further, a first light emitting electron tube lighting device 7 having such a control circuit for overcurrent regulation and using the lamp itself as a current limiting element, and a second light emitting electron tube lighting device having a current limiting element in addition to the lamp When the device 8 is combined and the filament heating power is supplied when the light emitting electron tube 2 is turned on or dimmed, the current limiting element is used by using the first light emitting electron tube lighting device 7. The light emitting electron tube 2 can be turned on or dimmed without using the light emission, and the circuit efficiency can be increased. On the other hand, when the filament heating power is not supplied,
By using the second light emitting electron tube lighting device 8,
The light emitting electron tube 2 can be turned on or dimmed according to any situation without falling into the uncontrollable state.

[0015]

FIG. 1 shows a first embodiment of the present invention. In the present embodiment, the light emitting electron tube 2 is turned on by the constant voltage power source 1, the lamp current is detected by the current detection circuit 3, and the filament heating power is controlled by comparing with the dimming signal in the preheating circuit. The light emitting electron tube 2 is intended to be stably turned on. For the above configuration, see FIG.
Although it is almost the same as the conventional example shown in FIG.
Furthermore, since the output current detection circuit 5 and the output current regulation circuit 6 are added to the constant voltage power source 1, and when the lamp current is trying to increase abnormally as shown in FIG. It works and regulates the lamp current so that it does not exceed a certain value. With such a configuration, it is possible to prevent the lighting device from being damaged,
It does not adversely affect the lamp. FIG. 2 shows the relationship between the preheating power Wf, the lamp voltage Vx, and the lamp current Vx when the ambient temperature Ta changes in this embodiment. Figure 1
As compared with the conventional example shown in FIG. 5, it can be seen that the abnormal increase in the lamp current after the preheating power Wf of the filament becomes zero is suppressed. The lamp current detection circuit 3
The voltage may be detected by a resistor, or a non-contact type by a hall element may be used, and the type thereof does not matter.

A second embodiment of the present invention is shown in FIGS. The terminals a, b, c, d, e, f, g and h in each figure are connected to each other. First, FIG. 3 shows the main circuit part, in which the commercial power supply is full-wave rectified by the diode bridge DB ₁ ,
The main power source is smoothed by the capacitor C ₂ . F
₁ is an overcurrent protection element (fuse), Z ₁ is an overvoltage protection element, C ₁ is a noise prevention capacitor, and FC ₁ is a noise prevention filter coil. R ₁ is the discharge resistance of the capacitor C ₂ , and the capacitor C ₃ is a noise-preventing capacitor that bypasses high frequencies. T ₁ is a down transformer basically having no leakage inductor, and the MOS transistors Q ₁ and Q ₂ are alternately turned ON / OF.
By repeating F, the stepped down high frequency AC voltage can be obtained. This is rectified by the rectifying element D _{1 and} smoothed by the capacitor C ₄ , and the lamp voltage Vx
On the other hand, the constant voltage power supply Vs that satisfies Vx≈Vs is obtained.
Note that R ₂ is a discharge resistance, and R ₃ and R ₄ are gate-source resistances of the MOS transistors Q ₁ and Q ₂ .

Q ₅ is a MOS transistor, which is turned off at the time of preceding preheating, and a voltage is not applied across the lamp. R ₇ is a gate-source resistance of the MOS transistor Q ₅ . Since the on-resistance of the MOS transistor Q ₅ is accurately specified,
The source-drain voltage of the transistor Q ₅ is proportional to the lamp current. Therefore, the terminal h can be used as a lamp current detection terminal. Further, the terminal g is a lamp voltage detection terminal. T _{2 is} also a down transformer similar to T ₁ , and includes MOS transistors Q ₃ and Q ₄ and resistors R ₅ and R
The functions of ₆ and the like are similar to those of the MOS transistors Q ₁ and Q ₂ and the resistors R ₃ and R ₄ .

Next, FIG. 4 shows a control power supply section, in which the voltage across the capacitor C ₁₁ is zener diode ZD ₁₁ at startup.
Transistor Q ₁₁ until the zener voltage of
Is turned on, and current flows through the capacitor C ₁₁ via the resistor R ₁₂ and the diode D ₁₁ . Then, after the control circuit shown in FIG. 5, which will be described later, operates, a current flows from the capacitor C ₄ to the capacitor C ₁₁ via the diode D ₁₂ . After that, since the voltage across the capacitor C ₄ is higher than the Zener voltage of the Zener diode ZD ₁₁ , the transistor Q ₁₁ is turned off.

Next, the control circuit section will be described. Figure 5
Is a lamp power control circuit. IC ₁₁Is switching
Integrated circuit for regulator control (manufactured by NEC Corporation μ
PC494C). This control integrated circuit IC₁₁Is
As is well known, power terminal (12th pin) and ground terminal
Control power supply voltage is applied between (Pin 7)
Connect between the terminal (pin 5) and the ground terminal (pin 7).
Capacitor C to be continued₁₂And the resistance terminal (6th pin)
Resistance R connected between the source terminals_{twenty three}Circumference according to the time constant of
It has a built-in oscillator that oscillates at the wave number. That first oscillation
The output is the first open collector terminal (pin 8) and the
The open emitter terminal (pin 9) of 1 is short-circuited
It is obtained by alternating the open state and the open state.
The second oscillation output is the second open collector (11
No. pin) and the second open emitter terminal (No. 10 pin)
The state in which the short circuit between
Obtained by. Here, output control terminal (Pin 13
Is available at the reference voltage output terminal (Pin 14)
When set to the level of the voltage Vref,
Performs shuffle operation and outputs the first oscillation output and the second oscillation output.
The force goes through the specified dead-off time and then reverses.
It Each output is a logic inverting circuit IC₁₄, IC₁₅To
More inverted shaping, MOS transistor Q₁, Q₂Control
Become a signal. In this embodiment, both outputs are Low level.
The bell period (dead off time) is short and H
A so-called push that repeats high level and low level
Is performing a pull operation.

Here, the high level of the terminals a and b and L
The output of the main circuit increases as the High level period (hereinafter referred to as “ON duty”) occupied in the repetition cycle of the ow level increases, and the output of the main circuit decreases as the ON duty decreases. Then, the lamp voltage is detected from the terminal g, and the ON duty is controlled so as to make the voltage constant. When the lamp current is detected from the terminal h and the detected value exceeds the specified value, it is prioritized over the previous lamp voltage control and the ON duty is controlled so that the lamp current does not exceed the specified value. ing.

Next, FIG. 6 shows a filament power control circuit. The IC _{12 is} also an integrated circuit for controlling a switching regulator (μPC494C manufactured by NEC Corporation),
Since its basic operation is almost the same as that of IC ₁₁ described above,
The description is omitted. The only difference is that the lamp voltage is not fed back from the terminal g, but only the lamp current is fed back from the terminal h. The variable resistor VR ₁₃ adjusts the preheating power by changing the ON duty, and is set to a desired dimming level. Then, if the lamp current is small compared with the lamp current detected from the terminal h, the ON duty given to the terminals c and d is controlled to be large so that a large amount of preheating power can be supplied, and conversely the lamp current is large. For example, the control is performed so as to perform the opposite operation.

Finally, FIG. 7 shows a timer circuit. IC
₁₃ is an integrated circuit for timer (manufactured by NEC Corporation μP
C1555) and operates as a monostable multivibrator. Capacitor C in the main circuit when power is turned on
_When the voltage of ₂ rises, the transistor Q ₁₂ is momentarily turned on via the resistor R ₃₂ and the capacitor C _16, and the falling trigger signal is applied to the 2nd pin connected to the resistor R ₃₃ and the collector of the transistor Q _12. It After that, for a fixed time determined by the time constant of the resistor R ₃₄ and the capacitor C ₁₅ , 3
The No. pin becomes High level, the transistor Q ₁₃ inverts it, and the terminal e becomes Low level. And after a certain time above, unless triggered again,
The terminal e continues to maintain the High level.

With the above structure, the lamp can be lit while the lamp voltage is kept constant during normal lighting, and no current limiting element apparently exists in the circuit. In addition, even if the lamp voltage drops and the filament heating power becomes zero and the lamp goes into an uncontrollable state, the lamp current is detected and controlled so that it does not exceed the specified value. There is no destruction by the lamp, and there is no serious adverse effect on the lamp.

In the present embodiment, the lamp used is a direct current lamp, but any lamp such as pulsating current, alternating current or high frequency may be used. Further, although a parallel inverter is used for both the main lighting circuit and the preheating circuit, a series inverter or a full bridge inverter may be used, and the type thereof is not particularly limited. In short, by controlling the filament heating power to control the lamp impedance and making the lamp itself the main current limiting element, the lamp current is regulated in the light emitting electron tube lighting device in which the current limiting element in the circuit is made small. Any circuit may be used as long as it has a limiting circuit that does not flow more than the value.

In the above-mentioned first or second embodiment, since the current limiting element is not required in the lighting device, it is advantageous in terms of cost and power loss, and other factors such as ambient temperature change. As a result, the lamp current does not become excessive and the lighting device is not destroyed, and this is a very effective means.
However, in these methods, since dimming is performed by the filament heating power, dimming is impossible when the preheating power becomes zero. Therefore, a circuit configuration as shown in FIG. 8 may be used. In this embodiment, in addition to the first lighting device 7 that includes the constant voltage power supply 1 shown in FIG. 1, the output current detection circuit 5 and the output current regulation circuit 6 and does not have a current limiting element, a current limiting element is provided. The second lighting device 8 is provided. When the filament heating power is not zero, the first lighting device 7 turns on the light emission electron tube 2 to control the filament heating power to perform dimming, which is the same as the above-described embodiment. Here, when the filament heating power becomes zero, dimming becomes impossible, but only at this time, if the light emitting electron tube 2 is turned on by the second lighting device 8 with a current limiting element, lighting is performed. Since the lamp current can be controlled from the device 8 side, dimming becomes possible. When the preheating power is required again, the light emitting electron tube 2 is turned on by the first lighting device 7, and when dimming is performed, the filament heating power may be controlled to perform dimming. With such a configuration, the circuit configuration becomes more complicated than that of the first or second embodiment, but it is possible to obtain a lighting device that enables dimming under any condition and has a small power loss. You can

[0026]

According to the first aspect of the invention, in the light emitting electron tube lighting device, the lamp impedance of the light emitting electron tube is controlled by controlling the filament heating power, and the lamp itself is a main current limiting element. Since it has a control circuit that controls the lamp current so that it does not flow beyond the specified value, even if the filament heating power becomes zero and the lamp impedance cannot be controlled, an excessive current does not flow in the lamp. In addition, it is possible to prevent the lamp from being adversely affected and the lighting device from being destroyed.

According to the second to fourth aspects of the present invention, the first light emitting electron tube lighting device is provided with the control circuit for regulating the overcurrent, and the lamp itself is the current limiting element, and the current limiting element other than the lamp. When the filament heating power is supplied when the light emitting electron tube lighting device is turned on or dimmed by combining the second light emitting electron tube lighting device having , The light emitting electron tube can be lit or dimmed without using a current limiting element, and the circuit efficiency can be improved, while the second light emitting electron tube is lit when the filament heating power is not supplied. By using the device, lighting or dimming can be performed under any condition without falling into the uncontrollable state, and compared with the case of only the lighting device having the current limiting element, There is an effect that the loss is less lighting device can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a main circuit unit used in a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a control power supply unit used in a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a lamp power control circuit used in a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a filament power control circuit used in a second embodiment of the present invention.

FIG. 7 is a circuit diagram of a timer circuit used in a second embodiment of the present invention.

FIG. 8 is a block diagram of a third embodiment of the present invention.

FIG. 9 is a circuit diagram of a first conventional example.

FIG. 10 is a circuit diagram of a second conventional example.

FIG. 11 is a circuit diagram of a third conventional example.

FIG. 12 is a circuit diagram of a fourth conventional example.

FIG. 13 is a circuit diagram of a fifth conventional example.

FIG. 14 is a circuit diagram of a sixth conventional example.

FIG. 15 is an operation explanatory view showing an operation with respect to a change in ambient temperature of a sixth conventional example.

FIG. 16 is an operation explanatory view showing an operation with respect to a change in mercury vapor pressure in a sixth conventional example.

[Explanation of symbols]

 1 constant voltage power supply 2 light emission electron tube 3 current detection circuit 4 preheating circuit 5 output current detection circuit 6 output current regulation circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyasu Eriguchi 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd.

Claims (4)

[Claims] 1. In a light emitting electron tube lighting device in which the lamp itself is a main current limiting element, the lamp impedance of the light emitting electron tube is controlled by controlling the filament heating power so that the lamp current does not flow beyond a specified value. 1. A light emitting electron tube lighting device, comprising a control circuit for controlling. 2. A control circuit for controlling the lamp impedance of the light emitting electron tube by controlling the filament heating power so that the lamp itself serves as a main current limiting element and the lamp current does not flow beyond a specified value. 1. A light emitting electron tube lighting device comprising: a first light emitting electron tube lighting device including the above; and a second light emitting electron tube lighting device including a main current limiting element in a circuit. 3. When the light emitting electron tube is turned on, when the filament heating power is supplied, it is turned on by the first light emitting electron tube lighting device, and when the filament heating power is not supplied, the second light emitting electron tube lighting device is used. The light emitting electron tube lighting device according to claim 2, which is turned on by the light emitting electron tube lighting device. 4. When dimming the light emitting electron tube, the first light emitting electron tube lighting device dims when filament heating power is supplied, and when the filament heating power is not supplied, 3. The light emitting electron tube lighting device according to claim 2, wherein the light emitting electron tube lighting device is dimmed.