JPH0546680B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention is directed to lighting a discharge lamp such as an amalgam-type fluorescent lamp, which uses an amalgam alloy to regulate the mercury vapor pressure inside the tube and improve lamp efficiency in a high-temperature region. The present invention relates to a discharge lamp lighting device, and particularly relates to a highly efficient discharge lamp lighting device when considering variations in characteristics of discharge lamps.

[Background technology]

Compact fluorescent lamps have been devised as an economical light source that can directly replace incandescent lamps, combining the high efficiency and long life of fluorescent lamps with the small size and single-cap structure of incandescent lamps. In a structure where the tube is sealed inside a globe, the mercury vapor pressure inside the tube increases and the luminous efficiency decreases, so various measures have been taken. Among them, low melting point metals that tend to form amalgams with mercury, e.g.
The amalgam method, which uses an In-Bi (indium-bismuth) alloy and takes advantage of the fact that the mercury vapor pressure of amalgam is maintained at a constant value even in high-temperature regions, is considered to be an excellent method with relatively few drawbacks.

Since the properties of this amalgam system are controlled by the amalgam temperature, efficiency can be maintained high over a wide range of ambient temperatures if maintained at an optimum temperature. In other words, in a normal discharge lamp, the temperature range in which the luminous flux exceeds 90% of the maximum value is approximately
In comparison to 30°C, amalgam discharge lamps can provide a temperature range of approximately 60°C.

On the other hand, the vapor pressure of an amalgam of alloy and mercury at room temperature is considerably lower than that of pure mercury, which reduces startability especially at low temperatures. It takes a considerable amount of time to be completely released and reach the optimum temperature, and there is also the disadvantage that a predetermined luminous flux cannot be obtained during that time.

Important technical issues for amalgam discharge lamps include how to accurately fill in the amount of mercury, how to maintain the temperature of the amalgam alloy optimally while the lamp is lit, and how to increase the luminous flux after startup. Examples include how quickly to do so.

Generally, in order to keep the temperature of the amalgam alloy at an appropriate temperature during lighting, the distance between the lamp filament and the amalgam alloy mounting part must be set appropriately, and in order to improve the rise of the luminous flux, it is necessary to separately install an auxiliary amalgam near the filament. Improvements have been made and significant improvements have been made.

The present inventor has proposed an In-
When a 15W amalgam lamp using a Bi-based amalgam alloy was operated at high frequency using an inverter device as shown in Fig. 5, it was discovered that it exhibited various characteristics as shown in Figs. 6 and 7.

In FIG. 5, a commercial power supply 1 is rectified and smoothed by a rectifier bridge 2 and a capacitor 3 to form a DC power supply, which includes a chiyoke coil 4, a transistor 7,
8, a push-pull inverter consisting of base resistors 5, 6, a capacitor 9, and an oscillation transformer 10 is configured, and the output winding of the oscillation transformer 10 has a 50KHz
of high-frequency power can be obtained. and a variable inductance 11 and an ammeter A for adjusting the lamp current,
The discharge lamp DL is turned on via the ammeter W. The light output of the discharge lamp DL is measured with a photometer Φ.

Using such a device, variable inductance 1
6 and 7 show the results of measuring the luminous flux and lamp current when the lamp current was varied according to No. 1. In the measurement, sufficient stabilization time was provided for each measurement point of the lamp current. The relationship between lamp current and luminous flux was as shown in Figure 6. In other words, for discharge lamps DL ₁ , the luminous flux increases even near the rated lamp current, and for discharge lamps DL ₂ and DL ₃ , the maximum luminous flux is at a point below the rated lamp current, and at higher lamp currents, the luminous flux increases. It was found that there were some cases in which the luminous flux suddenly decreased.

In addition, the lamp current at this time increases almost linearly as shown in Figure 7, and therefore, as the lamp current increases, the
It can be seen that the luminous efficiency of DL ₂ and DL ₃ decreases rapidly. It is known that in argon-based discharge lamps that do not use amalgam alloys, the luminous flux reaches saturation when the lamp current is increased, but no phenomenon has been observed in which the luminous flux suddenly decreases at a certain point. This phenomenon is considered to be unique to amalgam discharge lamps.

The cause of this phenomenon in amalgam discharge lamps has not yet been determined and remains at the level of speculation, but as mentioned above, it may be due to slight variations in the amount of mercury filled in or variations in the distance between the filament and the amalgam alloy. This is thought to be caused by the fact that the temperature of the amalgam part does not rise to the optimum value, and therefore the mercury vapor pressure becomes too high, leading to reabsorption of atoms and, as a result, an increase in non-radiative energy transfer. It is thought that this may be due to this. In other words, it is considered that the target amalgam was not formed due to variations in the discharge lamp.

If a lighting device is designed for such a discharge lamp, the following problems will occur. In other words, even if the output current of the lighting device is set near the rated lamp current for the discharge lamp DL ₁ shown in Fig. 6, depending on the dispersion of the discharge lamp, the output current may be lower than the target luminous flux like the discharge lamp DL ₃ . This results in a situation where only a significantly lower luminous flux is obtained.

[Purpose of the invention]

An object of the present invention is to provide a discharge lamp lighting device for lighting an amalgam type discharge lamp, which can efficiently light the discharge lamp regardless of variations in characteristics of the discharge lamp.

[Disclosure of the invention]

A discharge lamp lighting device according to a first aspect of the invention includes a variable output lighting device main body for lighting a discharge lamp containing an amalgam alloy, an output control circuit for changing the output of the lighting device main body, and an output control circuit for changing the output of the lighting device main body. a modulation means for making small periodic fluctuations; a photodetector for detecting the light output of the discharge lamp; Adjusting the output control circuit so as to increase the output of the lighting device main body and decrease the output of the lighting device main body when the change in the output of the lighting device main body and the change in the light output are in opposite directions. and output adjustment means.

The discharge lamp lighting device of the second invention adds an output change prohibiting means to the configuration of the first invention for prohibiting the output change of the lighting device main body when the light output exceeds a predetermined reference value.

A discharge lamp lighting device according to a third aspect of the invention includes, in addition to the configuration of the first invention, a lamp current detection means for detecting a lamp current of the discharge lamp, and a lamp current value detected by the lamp current detection means that exceeds a predetermined value. At times, an output increase prohibiting means for prohibiting an increase in the output of the lighting device main body is added.

In this way, the output of the lighting device main body is periodically slightly fluctuated by the modulation means, the light output of the discharge lamp is detected by the photodetector, and the output of the lighting device main body by the modulation device is adjusted by the output adjustment device. When the change in the output of the lighting device and the change in the light output are in the same direction, the output of the lighting device is increased, and when the change in the output of the lighting device and the change in the light output are in opposite directions, the output of the lighting device is decreased. Since the output control circuit is adjusted in this manner, the discharge lamp can be efficiently lit regardless of variations in characteristics of the amalgam discharge lamp to be lit.

In addition, if the output change prohibiting means is configured to prohibit the output change of the lighting device body when the light output exceeds a predetermined reference value, the light output may reach the predetermined level before the light output reaches the maximum. This can prevent the light output from becoming excessive and shorten the lamp life.

Further, the lamp current detection means detects the lamp current of the discharge lamp, and when the lamp current value detected by the lamp current detection means exceeds a predetermined value, the output increase prohibition means prohibits an increase in the output of the lighting device main body. By configuring this, it is possible to prevent the lamp life from becoming short.

Embodiment A first embodiment of the present invention will be described based on FIGS. 1 to 3. As shown in FIG. 1, this discharge lamp lighting device lights a discharge lamp 10 by a lighting device supplied with power from a commercial power source 1, and the lighting device is driven by an output control circuit. The output is changed according to the output of the output control circuit.

The output control circuit receives a modulation signal from the modulation signal circuit (one with a long cycle that the light output of the discharge lamp 10 can sufficiently follow), and changes the output of the lighting device slightly in accordance with the modulation signal. As a result, the light output of the discharge lamp 10 will also be slightly modulated.

The control level setting circuit provides a control level setting signal to the output control circuit to set the output of the lighting device to a predetermined value, and causes the discharge lamp 10 to generate a predetermined light output.

Therefore, the output control circuit to which the control level setting signal from the control level setting circuit and the modulation signal from the modulation signal circuit are applied has an output that is adjusted according to the modulation signal based on the level corresponding to the control level setting signal. will vary and therefore the output of the lighting device and the light output of the discharge lamp 10 will vary accordingly.

In the light detection/control level changing circuit, a photodetector a detects the light output level of the discharge lamp 10, and this detection level is set as a reference level (output from a reference level generator b) corresponding to a desired light output level. They are compared, and if the detection level is below the reference level, the difference is amplified by the differential amplifier c. Then, a slight variation is detected from the output of the differential amplifier c by a variation detector d. Furthermore, the increase/decrease signal generator e increases the optical output level when the output of the lighting device is increased by the modulation signal based on the output from the variation detector d and the output from the modulation signal circuit. If the light output level is in the direction of decreasing (the direction in which the light output level decreases when the output of the lighting device is decreasing), slightly change the control level setting value of the control level setting circuit to change the control level of the output control circuit. to slightly increase the output of the lighting device. Also, the direction in which the optical output level increases when the output of the lighting device is decreasing due to the modulation signal (the direction in which the optical output level decreases when the output of the lighting device is increasing)
If it is, the set value of the control level of the control level setting circuit is changed in the opposite way to the above, and the control level of the output control circuit is changed in the opposite way to the above, so that the output of the lighting device is slightly decreased.

The above operation is carried out while the discharge lamp 10 is lit.
By performing the operation at appropriate intervals, the discharge lamp 10
The output of the lighting device can be automatically adjusted in the direction of increasing the light output level of the discharge lamp 10, and the discharge lamp 10 using the target light output of the discharge lamp 10 as the upper limit can also be lit in a state with the highest light output. . Therefore, even if there are variations in the characteristics of the discharge lamp 10, it can be efficiently lit.

2 shows a detailed circuit diagram of the block diagram of FIG. 1, and FIG. 3 shows a waveform diagram of each part of FIG. 1.

In FIG. 2, the lighting device connected to a commercial power source 1 is connected to a DC power source obtained by rectifying the commercial power source 1 with a rectifier bridge 2, and is connected to voltage dividing capacitors 3, 4, switching transistors 8, 9, and diodes 6, Power is supplied to a half bridge inverter circuit consisting of 7, and the high frequency output from this half bridge inverter circuit is used to power a discharge lamp (amalgam type fluorescent lamp) via a chiyoke coil (ballast) 5.
10 is designed to be lit at high frequency. The half-bridge inverter circuit operates as drive transformers 15 and 1 according to a signal from the output control circuit.
6 and resistors 11 to 14, switch transistors 8 and 9 are alternately turned on and off to generate a high frequency output between the midpoint of voltage dividing capacitors 3 and 4 and the midpoint of switching transistors 8 and 9. I'm starting to do that.

The output control circuit is a circuit that generates drive signals for driving the switching transistors 8 and 9 described above, and further has a function of controlling the output of the lighting device by various signals described below. IC ₁ is a T flip-flop.
IC ₂ is a timer (general-purpose timer IC555, e.g. NE555 manufactured by Signateix), and the timer IC ₂ , external resistors 25 to 27, and capacitor 28 constitute an astable multivibrator, and its oscillation frequency is determined by the resistor. 25 to 27 and the time constant of the capacitor 28, and the potential of the No. 5 terminal of the timer IC ₂ . 29 is a modulation transistor that short-circuits the resistor 25, and 30 is a resistor. This output control circuit performs waveform processing on the output of the timer IC ₂ so that the T flip-flop IC ₁ and the gate circuits 21 to 24 do not turn on the switching transistors 8 and 9 at the same time. The output signal from 22 is supplied to the aforementioned drive transformers 15 and 16 via resistors 19 and 20 and transistors 17 and 18.

The control level setting circuit consists of BCD up/down counter (TC4510P) IC ₄ , IC ₅ and resistor 31.
This is a D-A conversion circuit consisting of a ladder resistance network consisting of ~46 circuits, and the oscillation frequency of the astable multivibrator of the output control circuit is set by various input signals (clock signal, up/down switching signal). It has the function of This control level setting circuit consists of BCD up/down counter IC ₄ ,
A clock signal, which will be described later, is applied to the clock terminal of IC ₅ , and the BCD up/down counters IC ₄ and IC ₅ count the clock signal. When the input signal to the up/down terminal is low level, The BCD up-down counters IC ₄ and IC ₅ count down, slightly reducing the DA conversion output voltage V ₀ , and transmitting this DA conversion output voltage V ₀ to the timer IC _{2 .}
Input to terminal 5 of. Therefore, timer IC ₂
Since the oscillation frequency of the astable multivibrator made up of the above increases, the on-off period of the switching transistors 8 and 9 also becomes shorter, and the reactance of the choke coil 5 increases, reducing the lamp input. Also, if the input signal of the up/down terminal is high level when the clock signal is input,
The lamp input is increased by the opposite operation to the above.

The light detection/control level change circuit detects the light output of the discharge lamp 10, compares it with a reference level, and determines the difference from the reference level when the light output level is below the reference level (corresponding to a desired light output level). The control level setting value of the control level setting circuit is changed based on the result, and the control level setting value of the control level setting circuit is changed. It includes a generator b, a differential amplifier c, a variation detector d, and an increase/decrease signal generator e. Specifically, the photodetector a includes a photodetection element (CdS element) 48 and resistors 47 and 5.
0 and a smoothing capacitor 52 for averaging the detection level, the reference level generator b is composed of resistors 49 and 51, and the differential amplifier c is composed of an operational amplifier IC ₃ and a capacitor 53 for noise prevention. It is composed of a feedback resistor 54 for stabilizing the amplification degree of the amplifier IC ₃ , and the fluctuation detector d is composed of resistors 55, 57, a capacitor 58, and a transistor 59.
and a resistor 60, and the increase/decrease signal generator e is composed of inverter gates 61 and 62.
The Zener diode 56, the transistor 79, and the resistor 78 constitute a circuit that prohibits changing the set value of the control level setting circuit (cuts off the clock signal) when the optical output level exceeds the reference level.

This light detection/control level changing circuit includes a light detection element 48 that receives light from a discharge lamp 10 and a resistor 4.
Voltage of the voltage divider circuit (discharge lamp 1
0) is applied to the negative terminal of operational amplifier IC ₃ , and the voltage divided by resistors 49 and 51 (reference level) is applied to the positive terminal of operational amplifier IC ₃ , and the difference is calculated by comparing the two. is amplified from operational amplifier IC ₃ and output. When the output of the operational amplifier IC ₃ is increasing, a charging current flows through the capacitor 58, and this charging current turns on the transistor 59, and conversely, when the output of the operational amplifier IC ₃ is decreasing, a charging current flows through the capacitor 58. In this case, no charging current flows through the capacitor 58, and the transistor 59 is off. The collector output of this transistor 59 is waveform-shaped by inverter gates 61 and 62 and applied to the up/down terminals of up/down counters _IC4 and _IC5 .

Furthermore, when the optical output increases from the reference value, the Zener diode 56 is activated by the output of the operational amplifier IC ₃ .
conducts, transistor 79 is turned on, and input of the clock signal to up-down counters IC ₄ and IC ₅ is prohibited.

The modulation signal circuit is for adding a fixed width modulation to the oscillation frequency of the astable multivibrator in the output control circuit.
IC555) IC ₆ and resistor 63, 64 and capacitor 6
5 and 66 constitute another astable multivibrator, and the output of this timer IC ₆ is connected to the base of a transistor 29 that short-circuits a resistor 25 for determining the oscillation frequency of the astable multivibrator in the output control circuit. It is input via a resistor 30. In addition, the output of the astable multivibrator using timer IC ₆ is sent to timer (general-purpose timer IC 555) IC ₇ and resistor via a delay circuit consisting of gate circuits 67, 70, resistors 68, 68A, diode 68B, and capacitor 69. 71 to 73, a diode 74, and capacitors 75, 76, and 77 _. It is designed to be supplied as a clock signal to the clock terminal of ₅ . In this case, the output pulse width of the monostable multivibrator is determined by the time constant of resistor 73 and capacitor 76, with capacitor 75 acting as a coupling capacitor for the trigger signal.

Next, the operation of this circuit will be explained in detail with reference to FIG.

A in FIG. 3 shows the output waveform of an astable multivibrator composed of timer IC ₆ , etc., and is a rectangular wave signal with a relatively long period. This square wave signal a is used as a timer.
Resistor 2 of resistors 25 and 26 that determines the oscillation frequency of the astable multivibrator composed of IC ₂ , etc.
By inputting the signal to the base of the transistor 29, which short-circuits the transistor 29, the output of the astable multivibrator composed of the timer IC ₂ and the like is modulated as shown in FIG. 3b.

The output of the gate circuit 67 to which the output of the astable multivibrator composed of the timer IC ₆ and the like is applied is an inverted waveform of the waveform a as shown in c of FIG. Furthermore, the output of the gate circuit 67 is connected to the resistor 6
8. When passed through the integrating circuit of the capacitor 69 and the gate circuit 70, the output becomes a rectangular wave having a falling edge during the low level period of the waveform a, like the waveform d in FIG. 3, and this rectangular wave signal Trigger the monostable multivibrator composed of timer IC ₇ , etc. by the falling signal e of d (momentarily lower the 2nd terminal (trigger terminal) of timer IC ₇ to a low level)
do. As a result, the monostable multivibrator composed of timer IC ₇ etc. outputs a signal with a waveform like f in Fig. 3, and this signal f is applied as a clock signal to up-down counters IC ₄ and IC ₅ . become.

On the other hand, g and g' in FIG. 3 show the waveforms at the connection point between the photodetector 48 and the resistor 47, and g is the section where the lamp input is increased by the modulation signal a described above (low frequency section). ) shows the situation when the light output of the discharge lamp 10 decreases, and g' shows the situation when the light output of the discharge lamp 10 increases in the section where the lamp input is increased by the modulation signal a. Also in this case, the light output of the discharge lamp 10 is lower than the standard level and therefore the light detection element 4
Since the resistance value of 8 is larger than the standard value, the operational amplifier
The potential of the negative terminal is higher than the reference level E _S of the positive terminal of IC ₃ , and the output DC level of operational amplifier IC ₃ is low, so the Zener diode 56
is not conductive. If the light output of the discharge lamp 10 exceeds the standard level, the potential of the negative terminal decreases, the output DC level of the operational amplifier IC ₃ increases, the Zener diode 56 becomes conductive, and the transistor 79 turns on. Therefore, the clock terminals to the up-down counters IC ₄ and IC ₅ are grounded through the diode 80, and no clock signals are input, so that the control level setting circuit stops changing the set value of the control level.

In the light output range where the Zener diode 56 does not conduct, the light output of the discharge lamp 10 also fluctuates in accordance with periodic fluctuations in the output of the lighting device, and this fluctuation is reflected in the resistors 55 and 57 and the capacitor 5.
8 and transistor 59. The transistor 59 is turned on by the charging current of the capacitor 58 during the period where the optical output increases, and the collector potential of the transistor 59 becomes a low level. Further, in the section where the optical output decreases, no charging current flows to the capacitor 58, the capacitor 58 is turned off, and the collector potential of the transistor 59 becomes a high level.
Therefore, the collector potential of the transistor 59 becomes as shown in h in Fig. 3 when the light output decreases in the section where the lamp input is increased, and conversely, when the light output decreases in the section where the lamp input increases. becomes like h' in Figure 3. The waveforms h and h' in Fig. 3 are transferred to the inverter gate 6.
1 and 62, i and i in Figure 3 respectively.
The waveform is shaped into a rectangular wave as shown by i' and input to the up/down terminals of up/down counters _IC4 and _IC5 .

Therefore, when the clock signal (f in FIG. 3) is input, that is, when the ramp input is large, if the input to the up/down terminal is at a high level as shown in waveform i, the up/down counter IC ₄ , IC ₅
counts up by 1, and the D-A conversion output voltage
V ₀ steps up by one step as shown in j in Fig. 3, and as a result, the oscillation frequency of the astable multivibrator composed of timer IC ₂ , etc. decreases as shown in k in Fig. 3, and the lighting device Increase the lamp input by increasing the output of the lamp. Conversely, when a clock signal is input, that is, when the ramp input is large, the input to the UP/DOWN terminal changes in waveform.
If the level is low like i', the up-down counters IC ₄ and IC ₅ count down by 1, and D-A
The converted output voltage V ₀ is stepped down by one step as shown in j' in Figure 3, and as a result, the oscillation frequency of the astable multivibrator consisting of timer IC ₂ etc. is increased as shown in k' in Figure 3. increases and decreases the output of the lighting device to reduce the lamp input.

When operated in this manner, the output of the lighting device changes in a direction in which the light output of the discharge lamp 10 increases, and becomes stable at the point where the light output reaches the maximum. In addition,
If the light output reaches the standard level before the light output reaches its maximum, the output of the lighting device will stabilize at this point.

In addition, in the above embodiment, as the photodetecting element 48,
Although a CdS element was used, it is also possible to use other phototransistors, photodiodes, etc.

A second embodiment of the invention will be described based on FIG. 4. This discharge lamp lighting device takes into consideration the fact that if the lamp current exceeds a certain value, the filament temperature will rise too much and the lamp life will be shortened.When the lamp current reaches the regulated current level,
The lamp input is stopped from increasing even if the light output is below the target value. That is, the current flowing through the discharge lamp 10 is detected by a current detection circuit, and a regulated current level (set by a regulated current level setting circuit) is determined by taking into account the lamp current value and the lamp life or the output capacity of the lighting device. ) with a comparator, and if the lamp current value is below the regulated current level, turn on the switch and control the output of the lighting device in the same way as in Figure 1. If the lamp current value exceeds the regulated current level, turn on the switch. It turns off, prohibits changes in the control level, and stops changes in the output of the lighting device. In this case, the light detection/control level changing circuit′
In this case, differential amplifier c in Fig. 1 is a simple amplifier.
c′ and also the reference level generator b of FIG.
, and components for limiting the maximum light output are omitted.

Other configurations and operations are shown in Figures 1 to 3.
Since it is as described in the explanation of the figure, details will be omitted.

In each of the above embodiments, a half-bridge inverter is used as the lighting device, but other inverter devices can also be used. Further, in the embodiment, switching transistors 8 and 9
Although the lamp input control was performed by changing the frequency of the drive signal, the lamp input control can also be performed using other methods, for example, by providing a variable impedance element on the output side of the inverter circuit and changing the impedance value. Furthermore, the lamp input can also be controlled by changing the input voltage of the impedance circuit using a chopper circuit, a phase control circuit, or the like. Further, even when a commercial copper-iron ballast is used as a lighting device, the same effect can be achieved by combining it with a phase control device.

〔Effect of the invention〕

According to the discharge lamp lighting device of the first aspect of the invention, the output of the lighting device main body is periodically slightly fluctuated by the modulation means, the light output of the discharge lamp is detected by the photodetector, and the light output of the discharge lamp is detected by the photodetector. When the change in the output of the lighting device main body due to the modulation means and the change in the light output are in the same direction, the output of the lighting device main body is increased, and when the change in the output of the lighting device main body and the change in the light output are in opposite directions. Since the output control circuit is adjusted to reduce the output of the lighting device itself, the discharge lamp can be lit efficiently regardless of variations in the characteristics of the amalgam discharge lamp to be lit. .

Further, according to the discharge lamp lighting device of the second invention,
The output change inhibiting means prohibits the output change of the lighting device body when the light output exceeds a predetermined reference value, so that when the light output reaches the predetermined level before the light output reaches the maximum, It is possible to stabilize the lamp, prevent the light output from becoming excessive, and prevent the lamp life from becoming short.

Furthermore, according to the discharge lamp lighting device of the third invention, the lamp current of the discharge lamp is detected by the lamp current detection means, and when the lamp current value detected by the lamp current detection means exceeds a predetermined value, the output is increased. Since an increase in the output of the lighting device main body is prohibited by the inhibiting means, shortening of the lamp life can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the first embodiment of the present invention, FIG. 2 is a detailed circuit diagram thereof, FIG. 3 is a waveform diagram of each part of the second embodiment, and FIG. 4 is a diagram of the second embodiment of the invention. An example block diagram, FIG. 5 is a circuit diagram of a conventional discharge lamp lighting device, and FIGS. 6 and 7 are characteristic diagrams of the discharge lamp, respectively. ... lighting device (lighting device main body), ... output control circuit, a ... photodetector, ... light detection/control level changing circuit (output adjustment means), ... control level setting circuit (output adjustment means), ...Modulation signal circuit (modulation means).

Claims (1)

[Scope of Claims] 1. A variable output lighting device main body for lighting a discharge lamp containing an amalgam alloy, an output control circuit for changing the output of the lighting device main body, and a control circuit for periodically and minutely decreasing the output of the lighting device main body. a photodetector for detecting the light output of the discharge lamp; Output adjustment means for adjusting the output control circuit so as to increase the output and decrease the output of the lighting device main body when a change in the output of the lighting device main body and a change in the light output are in opposite directions; Discharge lamp lighting device equipped with 2. The discharge lamp lighting device according to claim 1, wherein the lighting device main body lights the discharge lamp at high frequency using a high frequency inverter circuit. 3. A variable output lighting device main body for lighting a discharge lamp containing an amalgam alloy, an output control circuit for changing the output of the lighting device main body, and a modulation means for periodically slightly varying the output of the lighting device main body. a photodetector that detects the light output of the discharge lamp; and a photodetector that increases the output of the lighting device main body when the change in the output of the lighting device main body by the modulation means and the change in the light output are in the same direction; output adjustment means for adjusting the output control circuit so as to reduce the output of the lighting device main body when a change in the output of the lighting device main body and a change in the light output are opposite to each other; a discharge lamp lighting device, comprising: an output change prohibiting means for prohibiting an output change of the lighting device main body when a reference value of is exceeded. 4. The discharge lamp lighting device according to claim 3, wherein the lighting device main body lights the discharge lamp at high frequency using a high frequency inverter circuit. 5. A variable output lighting device main body for lighting a discharge lamp containing an amalgam alloy, an output control circuit for changing the output of the lighting device main body, and a modulation means for periodically and minutely varying the output of the lighting device main body; a photodetector that detects the light output of the discharge lamp; and a photodetector that increases the output of the lighting device main body when the change in the output of the lighting device main body by the modulation means and the change in the light output are in the same direction; an output adjusting means for adjusting the output control circuit so as to reduce the output of the lighting device main body when a change in the output of the lighting device main body and a change in the light output are in opposite directions; and a lamp of the discharge lamp. A discharge lamp lighting device comprising a lamp current detecting means for detecting current, and an output increase prohibiting means for prohibiting an increase in the output of the lighting device main body when the lamp current value detected by the lamp current detecting means exceeds a predetermined value. Device. 6. The discharge lamp lighting device according to claim 5, wherein the lighting device main body lights the discharge lamp at high frequency using a high frequency inverter circuit.