JPH07263156A - Discharge lamp lighting device and lighting device - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a discharge lamp lighting device and a lighting device capable of appropriately performing end-of-life determination even when different types of discharge lamps are used. A lamp current detection means 15 and a lamp voltage detection means 14 are provided, and one of the outputs of these means determines the end of life in a life end judgment means 16, and the other determines the judgment sensitivity of the life end judgment means 16. It is a discharge lamp lighting device and a lighting device which have a control means which changes and controls lighting of the discharge lamp 13 according to the judgment output of the end of life means 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device and a lighting device capable of detecting the end of life of a discharge lamp.

[0002]

2. Description of the Related Art A discharge lamp such as a fluorescent lamp often exhibits a half-wave discharge at the end of its life. In such a case, an excessive current will flow due to the direct current component, and the switching element will be destroyed and open or short-circuited. Further, as a secondary disaster, the ballast will be damaged due to abnormal temperature rise, smoke, or fire will occur. Also, as a result of an excessive current flowing through the discharge lamp, there is a risk that the base will melt due to an abnormal temperature rise when the base is made of plastics.

[0003] Therefore, the one that is constructed to solve the problem occurring at the end of life by detecting the end of life of the discharge lamp early and surely and controlling the operation of the ballast is put to practical use. ing.

FIG. 14 is a schematic circuit diagram of a conventional discharge lamp lighting device of this type described in Japanese Patent Laid-Open No. 4-39895. In this device, a high-frequency generating means 141 lights a discharge lamp 142, a voltage detecting means 143 for detecting a voltage across the discharge lamp 142, and a current detecting means 144 for detecting positive and negative current values flowing in the discharge lamp 142. Is provided. The output of the current detecting means 144 is compared by the comparing means 145, and when the positive / negative difference exceeds a predetermined value,
When the output of the voltage detection means 143 becomes equal to or higher than a predetermined value, the discharge lamp 142 determines that it is at the end of its life, and controls the output of the high frequency generation means 141.

Further, Japanese Patent Application Laid-Open No. 4-98796 discloses a discharge lamp lighting device similar to the above-mentioned conventional example.

Further, there has been known a device in which the end of life is detected only by one of the lamp voltage and the lamp current of the discharge lamp.

[0007]

However, in the above-mentioned prior art, when a plurality of types of discharge lamps having different load characteristics are configured to be able to be lit by the discharge stabilizing means of the same specification in any of the above-mentioned prior arts, the type of discharge lamp , The load characteristics are different, and therefore, the values are different regardless of whether the lamp current or the lamp voltage, and the end-of-life determination sensitivity greatly shifts. That is, if the sensitivity is set according to the load characteristics of any type of discharge lamp, the other types of discharge lamps cannot accurately detect the end of life. This is shown in Figure 2.
This will be described in detail in Section 3. That is, FIG. 2 is a graph showing changes in lamp current during the life of some types of discharge lamps. Rapid start type fluorescent lamp FLR40, F
Two types of LR40 / 36 and compact fluorescent lamp FPL
From the graph, it is possible to understand the difference between the characteristics of 36 and the total of 3 characteristics.
The case where the end of life is determined by detecting the change in the lamp current will be described as an example.
When it is set to determine the end of life when the value reaches, the life can be accurately determined with the rapid start type fluorescent lamp FLR40 / 36. However, in the case of the compact fluorescent lamp FPL36, it will be erroneously determined as the end of life at a stage quite before the end of life. On the contrary, in the case of the rapid start type fluorescent lamp FLR40 / 36, the end of life cannot be determined.

FIG. 3 is a graph showing the change in lamp voltage during the life of some types of discharge lamps. The type of discharge lamp is the same as in FIG. Even when the end of life is judged from this graph according to the lamp voltage detection signal, the tendency is opposite to that in FIG. 2, but basically there is the same problem as in the case of FIG.

Therefore, it is possible to adjust the sensitivity each time according to the type of discharge lamp used, but it is cumbersome and not practical. It is an object of the present invention to provide a discharge lamp lighting device and a lighting device in which the sensitivity is automatically adjusted regardless of which discharge lamp is used within the range of discharge lamps that are allowed in advance.

[0010]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device comprising a discharge stabilizing means for connecting an input end to a power source and an output end for a discharge lamp, and a half-wave discharge flowing at the end of the life of the discharge lamp. The discharge lamp reaches the end of its life according to the lamp current detection means capable of detecting the current, the lamp voltage detection means for detecting the lamp voltage of the discharge lamp, and the output of either the lamp voltage detection means or the lamp current detection means. The end of life determining means configured to change the determination level according to the output of the other, and the control means for controlling the lighting of the discharge lamp according to the output of the end of life determining means, It is characterized by having.

According to another aspect of the discharge lamp lighting device of the present invention, a discharge stabilizing means having an input terminal connected to a power source, a discharge lamp lit by the output of the discharge stabilizing means, and a half-wave discharge current flowing at the end of the life of the discharge lamp. The discharge lamp has reached the end of its life according to the detectable lamp current detection means, the lamp voltage detection means for detecting the lamp voltage of the discharge lamp, and the output of either the lamp voltage detection means or the lamp current detection means. And a control means for controlling the lighting of the discharge lamp according to the output of the end-of-life determination means, the end-of-life determination means configured to change the determination level according to the other output. It is characterized by having done.

According to another aspect of the discharge lamp lighting device of the present invention, an electronic discharge stabilizing means having an input end connected to a power source, a fluorescent lamp which is turned on by an output of the electronic discharge stabilizing means, and a semi-flowing lamp at the end of its life. Lamp current detection means capable of detecting the wave discharge current, lamp voltage detection means for detecting the lamp voltage of the fluorescent lamp, and the output of either the lamp voltage detection means or the lamp current detection means causes the fluorescent lamp to reach the end of its life. And a control for controlling the end-of-life determining means configured to change the determination level according to the other output, and the electronic discharge stabilizing means according to the output of the end-of-life determining means. And means are provided.

According to another aspect of the discharge lamp lighting device of the present invention, an electronic discharge stabilizing means having an input end connected to a power source, a discharge lamp which is turned on by an output of the electronic discharge stabilizing means, and a semi-flowing lamp which flows at the end of its life. Wave current detecting means capable of detecting the wave discharge current, lamp voltage detecting means for detecting the lamp voltage of the discharge lamp, and determining that the discharge lamp has reached the end of its life according to the output of the lamp current detecting means, and And a control means for controlling the electronic discharge stabilizing means in accordance with the output of the end-of-life determining means, the end-of-life determining means being configured to change the determination level according to the output of the lamp voltage detecting means. It is characterized by that.

The illuminating device according to claim 5 can detect a discharge stabilizing means having an input terminal connected to a power source, a discharge lamp lit by the output of the discharge stabilizing means, and a half-wave discharge current flowing at the end of the life of the discharge lamp. Lamp current detection means, lamp voltage detection means for detecting the lamp voltage of the discharge lamp, and the output of any one of the lamp voltage detection means and the lamp current detection means determines that the discharge lamp has reached the end of its life. And a control means for controlling the lighting of the discharge lamp in accordance with the output of the end-of-life determining means, the end-of-life determining means being configured to change the determination level according to the other output. A discharge lamp lighting device; and a lighting device main body in which the discharge lamp lighting device is provided;

[0015]

According to the present invention, the discharge lamp is stably lit by the discharge stabilizing means, the lamp current is detected by the lamp current detecting means, and the lamp voltage is detected by the lamp voltage detecting means. A predetermined detection signal of either the lamp current or the lamp voltage is input to the end-of-life determining unit as a signal to be determined. The end-of-life determining unit determines the end of life when the magnitude of the input signal is a predetermined value, and determines that it is not the end of life if it is not a predetermined value. The detection signal of the other one of the lamp current and the lamp voltage is input to the end-of-life determining unit so as to change or correct the determination level of the end-of-life determining unit. That is, the sensitivity for end-of-life determination is automatically adjusted within the allowable range regardless of which discharge lamp is used within the allowable range of discharge lamps. When the end of life is determined, the control means can control the lighting of the discharge lamp to prevent the occurrence of a disaster in advance.

According to the third aspect of the present invention, the same operation as that of the first and second aspects is performed, but the electronic discharge stabilizing means is used as the discharge stabilizing means, and the end of life is determined. The control means controls the electronic stabilization means. Therefore, the lighting of the fluorescent lamp is controlled so as to prevent the occurrence of a disaster.

According to the invention of claim 4, the end of life is determined by the lamp current detection signal, and the sensitivity of the life determination is adjusted by the lamp voltage detection signal.

According to a fifth aspect of the invention, there is provided a lighting device having the same function as that of the discharge lamp lighting device according to the first aspect.

[0019]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a conceptual diagram of a circuit according to the present invention. In the figure, 11 is a power supply such as a commercial AC power supply, 12 is a discharge stabilizing means such as an electronic stabilizing means, and 13 is a discharge lamp such as a fluorescent lamp. The input end of the discharge stabilizing means 12 is connected to the power supply 11, and the output end thereof is connected to the discharge lamp 13. Reference numeral 14 is a lamp voltage detecting means that is connected in parallel to the discharge lamp 13 to detect the lamp voltage of the discharge lamp, and 15 is connected in series with the discharge lamp 13 to directly or indirectly detect the lamp current of the discharge lamp 13. Lamp current detection means, 16 is an end-of-life judging means, and 17 is a control means. A predetermined one of the lamp voltage detection signal and the lamp current detection signal is input to the end-of-life determining unit 16 as a signal for determining the end of life. The other detection signal is input to change or correct the determination sensitivity.

Next, the operation of the embodiment shown in FIG. 1 will be described. Electric energy is supplied to the discharge lamp 13 from the power supply 11 via the discharge stabilizing means 12, and the discharge lamp 13 is turned on. The lamp voltage of the discharge lamp 13 is monitored by the lamp voltage detecting means 14, and the lamp current is monitored by the lamp current detecting means 15. When the preselected one of the lamp voltage and the lamp current of the discharge lamp 13 reaches a preset value, the end-of-life determining unit 16 determines that the end of life is reached. When the end-of-life determining unit 16 determines that the end of life is reached, the control unit 17 operates and the lighting of the discharge lamp 13 is controlled.

On the other hand, the output of the other detecting means 15 or 14 is inputted to the life judging means 16 so as to change or correct the judgment sensitivity of the life judging means 16.

Next, the correction of the determination sensitivity will be described.
As shown in FIGS. 2 and 3, the lamp current and the lamp voltage of the discharge lamp gradually increase during the life. The discharge lamp of the type in which the amount of change in lamp current is large has a relatively small amount of change in lamp voltage.

On the contrary, the discharge lamp of the type having a small change in the lamp current has a large change in the lamp voltage. From each figure, it can be understood that the lamp current and the lamp voltage have a complementary relationship.

Therefore, a case where the end of life is determined based on the lamp current detection signal will now be described. For example, when the compact fluorescent lamp FPL36 is used, the lamp current detection signal has a high signal level in the same life process, but the lamp voltage detection signal has a low signal level. Therefore, the determination sensitivity of the life determination means 16 depends on the latter signal level. It can be lowered automatically. Of course, rapid start type fluorescent lamp FL
It can be easily understood that in the case of R40, the determination sensitivity of the life determining unit 16 can be increased. In the case of the rapid start type fluorescent lamp FLR40 / 36, it is about the middle of the above two. By doing as described above, the end-of-life determination sensitivity is automatically corrected according to the type of discharge lamp.

FIG. 4 is a circuit diagram showing an example of the lamp voltage detecting means. In the figure, 41 and 42 are resistors for voltage division connected in series between both ends of the discharge lamp 13, 43 and 44 are capacitors and diodes connected in series between both ends of the resistor 42, and 45 is a capacitor 43 and a diode 44. At the connection point, one end is connected in series with the diode 44 in the forward direction, and the diode 46 is a diode 44,
It is a smoothing capacitor connected in parallel with 45. The lamp voltage detection signal is obtained from both ends of the capacitor 46.

The lamp voltage of the discharge lamp is divided by the resistors 41 and 42, the voltage drop voltage of the resistor 42 is voltage-doubled and rectified, and a lamp voltage detection signal is obtained from the other end of the diode 45. For example, it is input to the end-of-life determining unit 16 as the determination sensitivity correction. FIG. 5 is a circuit diagram showing another example of the lamp voltage detecting means. In this example, one lamp voltage detecting means is provided for the two discharge lamps 13, 13 that are turned on in series. Further, capacitors 51 and 52 are connected in series as the voltage dividing elements in series between the outer ends of the discharge lamps 13 and 13. Since other configurations are the same as those in FIG. 6, the same portions are denoted by the same reference numerals and the description thereof will be omitted. The operation is basically the same as in FIG.

FIG. 6 is a circuit diagram showing an example of the lamp current detecting means 15. In the figure, 61 is a capacitor inserted in series in the discharge circuit, and 62 and 63 are resistors, which equally divide the terminal voltage of the capacitor 61. Reference numerals 64 and 65 are diodes, which direct the DC voltages of different polarities appearing between the terminals of the resistors 62 and 63 to the same polarity and guide them to the output side. 66 is a smoothing capacitor. This example is suitable for the half-bridge inverter of FIG. 10 described later.

When the discharge lamp reaches the end of its life and half-wave discharge occurs, a positive or negative half-wave voltage appears across the capacitor 61. In the case of the polarity shown, the terminal voltage of the resistor 62 causes the diode 64 to pass through. Through which the capacitor 66 is charged to the polarity shown. When the voltage appearing across the capacitor 61 is opposite to that shown, the terminal voltage of the resistor 63 passes through the diode 65 and charges the capacitor 66 to the polarity shown. Therefore, when the half-wave discharge occurs, the lamp current detection signal is input to the end-of-life determination unit 16 as a signal for the end-of-life determination, regardless of the polarity.

FIG. 7 is a circuit diagram showing another example of the lamp current detecting means 15. In the figure, 71 is a current transformer inserted in series with the capacitor 61, and other parts are shown in FIG.
Therefore, the same reference numerals are given and the description thereof will be omitted.
This example is suitable for the monolithic inverter shown in FIG. 9, which will be described later. By detecting the half-wave discharge across the current transformer 71, it is possible to prevent a direct current component from flowing through the current transformer 71 and thereby prevent the inverter from operating abnormally.

FIG. 8 is a circuit diagram showing an example of the end of life judging means 16. In the figure, reference numeral 81 is a comparator, and a lamp current detection signal is input to its input terminal a, and an end-of-life judgment output is sent to the control means 17 from the output terminal. The output of the correction circuit 82 is input to the reference signal terminal b. The correction circuit 82 mainly includes a transistor 82a whose conductivity changes according to the output of the lamp voltage detection means 14. The collector of the transistor 82a is connected to the reference signal terminal b of the comparator 81. In the figure, 82b, 82
c, 82d and 82e are resistors, and 82f is a Zener diode.

When the output of the lamp voltage detecting means 14 is small according to the type of discharge lamp, the base current of the transistor 82a becomes small, so that the conductivity is small and the collector potential rises. Therefore, the reference signal applied to the reference signal terminal b rises.

Depending on the type of discharge lamp, even if the detection signal of the lamp current detection means 15 input to the input terminal a becomes large, the reference signal also rises, so that the comparator 82 produces an output. , The lamp current detection signal must rise further. That is, the determination sensitivity of the end-of-life determining unit 16 becomes relatively dull by the lamp voltage detecting unit 14 and the correction circuit 82. On the contrary, when the output of the lamp voltage detecting means 14 increases according to the type of discharge lamp, the base current of the transistor 82a increases and the conductivity increases, so that the collector potential decreases. Therefore, the reference signal applied to the reference signal terminal b decreases. Therefore, even if the output of the lamp current detecting means 15 is relatively reduced, the determination sensitivity of the end-of-life determining means 16 is sharpened due to the decrease in the reference signal, so that the end of life can be appropriately determined. As described in detail above, when the end of life judgment is made by either the lamp current or the lamp voltage, the judgment sensitivity is automatically corrected by the other, so even if the type of discharge lamp used changes, it is within the allowable range. Always make appropriate judgments.

FIG. 9 is a circuit diagram showing an example in which the discharge stabilizing means 12 is constituted by an electronic stabilizer. The figure constitutes a one-stone inverter, and in the figure 91 is a power source 11
A rectifying circuit that rectifies and smoothes the alternating current of
Reference numeral 93 is a main switching element of the inverter. Reference numeral 94 is an output transformer, 94a is a primary winding thereof, 94b is a secondary winding thereof, and 95 is a capacitor which is connected in parallel with the primary winding 94a and constitutes a resonance circuit together with the output transformer. 9
6 is a current transformer connected in series with the secondary winding 94b,
The necessary energy for self-oscillation of the main switching element 93 is supplied to give switching timing. 97
Is a capacitor inserted in the excitation circuit of the switching element 93 and determines the oscillation frequency.

FIG. 10 is a circuit diagram showing another example of the discharge stabilizing means 12. This is an electronic ballast with a half-bridge inverter. That is, a pair of switching elements 101 and 102 are connected in series to a DC power source, and an inductor 103 is connected in series between a connection point between the switching elements 101 and 102 and a connection point between the switching element 102 and the DC power source. The discharge lamp 13 is connected via, for example, an output transformer (not shown) 104. 104 is a switching element 101, 102
Is a drive circuit for switching alternately. In the figure, the same parts as those in FIG. 9 are designated by the same reference numerals and the description thereof will be omitted. FIG. 11 is a circuit diagram showing an example of the control means 17 in FIG. The control means 17 is a photocoupler light-emitting diode 111 that responds to the determination output of the end-of-life determination means 16, a photocoupler phototransistor 112 that is turned on in response to this light emission, and is on when the phototransistor 112 is off. Transistor 11
3 and 3 as main constituent elements.

On the other hand, in FIG. 11, the discharge stabilizing means 12 is the one-stone inverter shown in FIG. 9, but the capacitor 97 of the excitation circuit is divided into two capacitors 97a and 97b which are connected in parallel, and one capacitor 97b. Is connected in series with the transistor 113. 11 in the figure
Reference numeral 4 denotes a capacitor charged from a DC power supply via a resistor 115, and the phototransistor 112 and a series circuit of resistors 116 and 117 are connected in parallel with the capacitor 11. A capacitor 118 is connected in parallel with the resistor 117, and the base of the transistor 113 is turned on / off according to the terminal voltage of the capacitor so that the base of the transistor 113 is connected via the resistor 119.
8 is connected to one end.

In the present invention, the discharge stabilizing means is shown in FIGS.
The discharge stabilizing means is not limited to the above, and various discharge stabilizing means can be used.

Next, the operation of the control means 17 shown in FIG. 11 will be described. When a determination output is obtained from the end-of-life determining unit 16 because the lamp current or the lamp voltage, whichever is the predetermined value, for example, the value of the lamp current exceeds the set value, the light emitting diode 111 of the photocoupler emits light. Along with this, the phototransistor 112 is turned on. As a result, the potential of the capacitor 118 is lowered and the transistor 113 is turned off. As a result, the capacitor 97b is opened, so that the oscillation frequency of the one-stone inverter increases. As a result, the load current of the inverter, that is, the lamp current is significantly reduced. That is, the lighting of the discharge lamp is controlled, and various accidents accompanying the occurrence of half-wave discharge at the end of life are prevented.

FIG. 12 is a circuit diagram showing another example of the control means 17. This example is suitable for the discharge stabilizing means mainly including the half-bridge inverter shown in FIG. 10, and uses the integrated circuit 121. The integrated circuit 121 is configured so that the various protection devices and those used for controlling the oscillation of the inverter are also used for the end of life protection. That is, the transistor 12 that is turned on by the output of the end-of-life determining unit
2. When this is turned on, a signal is input between the predetermined control input terminals c and d of the integrated circuit 121 via the resistors 123 and 124. As a result, a control signal is sent from the output terminal e of the integrated circuit 121, and the drive circuit of the inverter significantly narrows the output of the inverter by this control signal or stops the operation if necessary.

FIG. 13 is a front view showing an example of the illumination device of the present invention. In the figure, 131 is a lighting device main body, 13
Reference numerals 2 and 132 are sockets, and 133 is a discharge lamp lighting device, of which the discharge lamp is indicated by 13. Blinking of the lighting device is controlled by a switch (not shown) provided inside the device body or a switch (not shown) provided outside the body.

The present invention is not limited to the above description and allows various modifications. For example, a switch may be interposed between the discharge stabilizing means and the discharge lamp or between the power source and the discharge stabilizing means, and the switch may be opened to turn off the discharge lamp by a control signal at the end of life. In addition to substantially turning off the discharge lamp, the discharge of the discharge lamp may be controlled so that the end of life can be displayed, for example, dimming or intermittent discharge may be performed. As the discharge stabilizing means, not only the electronic discharge stabilizing means, but a discharge stabilizing means composed of an iron core and a coil may be used. The electronic discharge stabilizing means is not limited to the one-stone type and the half bridge type. For example, any inverter such as a full bridge type or a parallel type may be used. The power source may be any power source such as a DC power source, for example, a battery power source, in addition to the commercial AC power source. Furthermore, the number of discharge lamps is arbitrary. Not only fluorescent lamps but also other discharge lamps such as germicidal lamps are allowed.

[0042]

[Effect] The present invention has the following effects because of the structure and operation as described above in detail.

According to the first to fifth aspects of the present invention, the end of life judgment is made by either one of the lamp current and the lamp voltage, and the sensitivity of the judgment is automatically changed or corrected by the other, so that the type of discharge lamp can be changed. Even if they are different, the end of life judgment can be appropriately performed, and therefore, it is applicable to a plurality of types of discharge lamps without changing the specifications of the discharge stabilizing means.

In particular, according to the third aspect of the invention, when the end of life is detected, the electronic discharge stabilizing means is controlled to control the lighting of the discharge lamp, so that the control is easy and the configuration can be simplified.

In particular, according to the invention of claim 4, in addition to the effect of claim, the end of life is determined by the lamp current,
The determination sensitivity can be changed by the lamp voltage.

Particularly, according to the invention of claim 5, it is possible to provide a lighting device having the same effect as that of the invention of claim 1.

[Brief description of drawings]

FIG. 1 is a circuit conceptual diagram showing an embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a graph showing a change in lamp current during the life of the discharge lamp.

FIG. 3 is a circuit diagram showing a change in lamp voltage during the life of the discharge lamp.

FIG. 4 is a circuit diagram showing an example of a lamp voltage detecting means of the present invention.

FIG. 5 is a circuit diagram showing another example of the lamp voltage detecting means of the present invention.

FIG. 6 is a circuit diagram showing an example of a lamp current detecting means of the present invention.

FIG. 7 is a circuit diagram showing another example of the lamp current detecting means of the present invention.

FIG. 8 is a circuit diagram showing an example of end-of-life determining means according to the present invention.

FIG. 9 is a circuit diagram showing an example of discharge stabilizing means of the present invention.

FIG. 10 is a circuit diagram showing another example of the discharge stabilizing means of the present invention.

FIG. 11 is a circuit diagram showing an example of control means of the present invention.

FIG. 12 is a circuit diagram showing another example of the control means of the present invention.

FIG. 13 is a front view showing an example of a lighting device of the present invention.

FIG. 14 is a circuit diagram showing a conventional discharge lamp lighting device.

[Explanation of symbols]

 Reference Signs List 11 power supply 12 discharge stabilizing means 13 discharge lamp 14 lamp voltage detecting means 15 lamp current detecting means 16 end-of-life determining means 17 control means

Claims (5)

[Claims] 1. A discharge stabilizing means having an input terminal connected to a power source and an output terminal connected to a discharge lamp; lamp current detecting means capable of detecting a half-wave discharge current flowing at the end of the life of the discharge lamp; Lamp voltage detecting means for detecting the lamp voltage; determining whether the discharge lamp has reached the end of its life according to the output of either the lamp voltage detecting means or the lamp current detecting means, and determining according to the output of the other End-of-life judging means configured to change the level; control means for controlling lighting of the discharge lamp according to the output of the end-of-life judging means;
A discharge lamp lighting device comprising: 2. A discharge stabilizing means having an input terminal connected to a power source; a discharge lamp lit by the output of the discharge stabilizing means; and a lamp current detecting means capable of detecting a half-wave discharge current flowing at the end of the life of the discharge lamp. Lamp voltage detecting means for detecting the lamp voltage of the discharge lamp; and it is judged that the discharge lamp has reached the end of its life according to the output of either the lamp voltage detecting means or the lamp current detecting means, and the other output Discharge lamp, characterized in that: the end-of-life determining means configured to change the determination level according to the above; and a control means for controlling lighting of the discharge lamp according to the output of the end-of-life determining means; Lighting device. 3. An electronic discharge stabilizing means having an input terminal connected to a power source; a fluorescent lamp lit by the output of the electronic discharge stabilizing means; a lamp capable of detecting a half-wave discharge current flowing at the end of the life of the discharge lamp. Current detecting means; lamp voltage detecting means for detecting the lamp voltage of the discharge lamp; and determining that the discharge lamp has reached the end of its life according to the output of either the lamp voltage detecting means or the lamp current detecting means, And the end-of-life judging means configured to change the judgment level according to the other output; and the control means for controlling the electronic discharge stabilizing means according to the output of the end-of-life judging means. Characteristic discharge lamp lighting device. 4. An electronic discharge stabilizing means having an input terminal connected to a power source; a discharge lamp lit by the output of the electronic discharge stabilizing means; a lamp capable of detecting a half-wave discharge current flowing at the end of the life of the discharge lamp. Current detecting means; lamp voltage detecting means for detecting the lamp voltage of the discharge lamp; and determining that the discharge lamp has reached the end of its life according to the output of the lamp current detecting means,
And an end-of-life determining unit configured to change the determination level according to the output of the lamp voltage detecting unit; and a control unit for controlling the electronic discharge stabilizing unit according to the output of the end-of-life determining unit. A discharge lamp lighting device characterized in that 5. A discharge stabilizing means having an input terminal connected to a power source, a discharge lamp lit by the output of the discharge stabilizing means, and a lamp current detecting means capable of detecting a half-wave discharge current flowing at the end of the life of the discharge lamp. A lamp voltage detecting means for detecting the lamp voltage of the discharge lamp, and one of the lamp voltage detecting means and the lamp current detecting means determines that the discharge lamp has reached the end of its life, and the other output A discharge lamp lighting device comprising: a life end judgment means configured to change the judgment level according to the above; and a control means controlling lighting of the discharge lamp according to an output of the life end judgment means; An illuminating device main body provided with a discharge lamp lighting device;