JPH03110794A - Lighting device for discharge lamp - Google Patents

Abstract

PURPOSE:To keep the dimming ratio of a discharge lamp nearly constant by controlling the oscillation state of an inverter circuit depending upon the output of a temperature detecting means. CONSTITUTION:A temperature detecting means 8 is provided to detect the temperature in a lighting fitting, and a control circuit 9 is provided to control the oscillation state of an inverter circuit 4 to switch the full lighting and the dimmed lighting of a discharge lamp 5, and to vary the output of the inverter circuit 4 by controlling the oscillation state of the inverter circuit 4 depending upon the output of the temperature detecting means 8. Therefore, even when the luminous efficiency of the discharge lamp in the full lighting and the dimmed lighting is varied by the temperature variation in the lighting fitting respectively, the output of the inverter circuit 4 can be varied correspondently. Thereby the dimming ratio of the discharge lamp can be kept nearly constant.

Description

Detailed Description of the Invention [Field of Industrial Application] This invention supplies power to an inverter circuit including switching elements from a DC power obtained by rectifying and smoothing a commercial power supply, and The present invention relates to a discharge lamp lighting device capable of stepwise dimming, which supplies high-frequency power to a discharge lamp such as a lamp to light the discharge lamp.

[Traditional techniques]

Conventionally, in the field of lighting equipment, especially in the field of lighting equipment equipped with discharge lamps, high-frequency lighting using an inverter circuit has been used as a discharge lamp lighting device for lighting discharge lamps in terms of light output efficiency and ease of output control. Therefore, many discharge lamp lighting devices using inverter circuits have been developed.

However, no matter how easy the inverter circuit is in terms of output control, the current situation is that it is not possible to fully control the characteristics of the discharge lamp itself.

As a characteristic of a discharge lamp, the light output when the current flowing through the discharge lamp is constant, regardless of the temperature of the tube wall of the discharge lamp, or in other words, the luminous efficiency, as shown in Figure 10, the luminous efficiency is plotted on the vertical axis. When the horizontal axis represents the tube wall temperature, the characteristic becomes a negative quadratic curve with respect to changes in the tube wall temperature. As is clear from FIG. 10, the luminous efficiency decreases at both low and high temperatures compared to at room temperature. Also,
Regarding startability, there was also a problem in that if the current of the discharge lamp was small, starting at low temperatures became difficult.

For example, Japanese Patent Application No. 63-24527
Improvements have been made to No. 6 to improve starting performance and ensure good output.

In a lighting equipment, even if the lighting equipment is in good condition at the time of startup, the internal temperature rises after the discharge lamp is turned on, and the light output until it stabilizes follows the course shown in FIG. 11.

In FIG. 11, a solid line A1 shows a change in the light output when the light is fully lit, and a solid line A2 shows a change in the light output when the light is dimmed.

When the discharge lamp is started when the lamp is fully lit, the temperature of the tube wall of the discharge lamp has not yet risen, so the solid line A in Fig. 11
As shown in Figure 1, once the output is reached, the temperature inside the lighting equipment rises, and the temperature of the tube wall of the discharge lamp also rises due to the heat generated by the discharge lamp.As shown in Figure 1O, as the temperature rises, light is emitted. As the efficiency decreases, the optical output gradually decreases and reaches a constant value at a certain stable point.

However, during dimming lighting, the current applied to the discharge lamp is reduced, so the temperature rise of the discharge lamp itself is small, and the output remains constant, drawing an upward curve as shown by the solid line A2 in FIG. In other words, when all lights are on, the first
This is because point A in Figure 0 is the luminous efficiency point during stable lighting, and point B is the luminous efficiency point during stable lighting during dim lighting.

[Problem to be solved by the invention]

Recently, however, due to the diversification of designs, lighting fixtures with no exposed discharge lamp are now on the market.

In such lighting equipment, the temperature of the discharge lamp tends to be higher than that in one in which the discharge lamp is exposed. This is because the discharge lamp, lighting circuit, etc. are enclosed within the lighting fixture, and the discharge lamp is hardly cooled by the outside air.

In the case of a type of lighting fixture in which the discharge lamp is not easily cooled, the light output of the discharge lamp follows a course as shown in FIG. 12 until it stabilizes after lighting. In FIG. 12, the solid line B1 shows the change in light output when all lights are on, and the solid line B2
indicates the change in light output during dimming lighting. Note that the broken line C1 shows the same curve as the solid line A1 in FIG. 11, and the broken line C2
indicates the same curve as the solid line A2 in FIG.

When the lamp is fully lit, if the temperature inside the lighting equipment becomes higher, the operation around the time of starting will not change much, but the temperature of the tube wall of the discharge lamp will rise more than in the case shown in Figure 11, and the light at this time will be lower. The output stabilizes at a lower point than in the case of FIG. In FIG. 10, when the lights are all lit up, point A' is the stable luminous efficiency point.

However, when the lamp is dimmed, the current flowing through the discharge lamp is small, so the temperature of the discharge lamp tube wall increases only slightly.
In this case, the optical output is stabilized at a point where it is slightly increased compared to the case shown in FIG. In Figure 10, when lighting is dimmed, B'
The point is the stable luminous efficiency point. Note that in this example, it has been explained that in a lighting fixture with poor heat dissipation, the light output increases during dimming lighting, but depending on the design of the lighting fixture, the light output may decrease.

Therefore, if a lighting fixture with a large internal temperature rise is designed in the same way as a lighting fixture with a small internal temperature rise, the dimming ratio at stable time (dimming lighting output at stable time / lighting output at stable time) (total lighting light output) becomes large,
There was a problem in that the amount of light did not change between full lighting and dimmed lighting.

An object of the present invention is to provide a discharge lamp lighting device that can make the dimming ratio of the discharge lamp the same regardless of the difference in temperature within the lighting equipment during stable lighting.

[Means to solve the problem]

The discharge lamp lighting device according to claim 11 is a discharge lamp lighting device that converts the voltage of a DC power source into a high frequency voltage using an inverter circuit and supplies the high frequency voltage to the discharge lamp, which is provided with a temperature detection means for detecting the temperature inside the lighting equipment. In addition, control is provided to change the output of the inverter circuit by controlling the oscillation state of the inverter circuit to switch between full lighting and dimmed lighting of the discharge lamp, and to control the oscillation state of the inverter circuit in accordance with the output of the temperature detection means. A circuit is installed.

In the discharge lamp lighting device according to claim (2), the control circuit is configured to reduce the output of the inverter circuit during dimming lighting in response to a rise in temperature within the lighting equipment.

In the discharge lamp lighting device according to claim (3), the control circuit is configured to increase the output of the inverter circuit when the lamp is fully lit in response to a rise in temperature within the lighting equipment.

[For production]

According to the configuration described in claim (1), since the oscillation state of the inverter circuit is controlled according to the output of the temperature detection means,
Even if the luminous efficiency of the discharge lamp changes during full lighting and dimmed lighting due to temperature changes inside the lighting equipment,
Accordingly, the output of the inverter circuit can be changed, and the dimming ratio of the discharge lamp can be kept substantially constant.

According to the configuration described in claim (2), the dimming ratio of the discharge lamp can be kept substantially constant by reducing the output of the inverter circuit during dimming lighting in response to a rise in the internal temperature of the lighting equipment. I can do it.

According to the configuration described in claim (3), by increasing the output of the inverter circuit during full lighting in response to a rise in the internal temperature of the lighting equipment, the dimming ratio of the discharge lamp can be kept substantially constant. can. In this case, the change in light output due to temperature rise inside the lighting equipment is large when it is fully lit, so if the dimming ratio is kept approximately constant by increasing the output when fully lit, the light output of the discharge lamp The temperature itself can be maintained substantially constant regardless of temperature changes within the lighting equipment.

〔Example〕

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

FIG. 1 shows a discharge lamp lighting device according to a first embodiment of the present invention. In FIG. 1, l is a DC power source, for example, a commercial power source 2 and a rectifying/smoothing circuit 3 for rectifying and smoothing the voltage. configured. Reference numeral 4 denotes an inverter circuit including a switching element and a resonant circuit, and its internal configuration may be of any configuration as long as it can change the oscillation frequency.

Reference numeral 5 denotes a discharge lamp such as a fluorescent lamp which is supplied with power from the inverter circuit 4 and is lit at high frequency.

7 is an oscillation circuit that determines the oscillation frequency of the inverter circuit 4;
6 is an inverter circuit 4 based on the oscillation output of the oscillation circuit 70.
8 is a temperature detection means for detecting the temperature inside the lighting equipment, for example, the temperature of the tube wall of the discharge lamp 5.

9 controls the oscillation state of the inverter circuit 4 by supplying a signal to the oscillation circuit 7 to switch between full lighting and dimmed lighting of the discharge lamp 5, and also oscillates in accordance with the output of the temperature detection means 8 in the same manner as above. By giving a signal to the circuit 7, the oscillation state of the inverter circuit 4 is controlled and the inverter circuit IB4 is
This is a control circuit that changes the output of the

In this case, the control circuit 9 specifically switches the oscillation frequency of the oscillation circuit 7 using a full lighting/dimming lighting switching means (not shown) such as a switch, thereby controlling the full lighting/dimming lighting of the discharge lamp 5. The output of the inverter circuit 4 is changed by changing the oscillation frequency of the oscillation circuit 7 according to the output of the temperature detection means.

The change in the oscillation frequency of the oscillation circuit 7 according to the output of the temperature detection means 8 described above is performed only when dimmed lighting, only when fully lit, and both when fully lit and when dimmed lighting. There may be cases.

With the above configuration, this discharge lamp lighting device can not only switch between full lighting and dimming lighting of the discharge lamp 5, but also control the oscillation state of the inverter circuit 4 according to the output of the temperature detection means. Therefore, even if the luminous efficiency of the discharge lamp 5 changes in both full lighting and dimmed lighting due to temperature changes within the lighting equipment, the output of the inverter circuit 4 can be changed accordingly. , the dimming ratio of the discharge lamp 5 can be kept substantially constant.

In this case, the output change in order to keep the dimming ratio of the discharge lamp 5 substantially constant can be achieved by reducing the output of the inverter circuit 4 in response to the temperature rise within the lighting equipment only during dimming lighting, or A method of increasing the output of the inverter circuit 4 in response to a temperature rise within the lighting equipment only when the lighting equipment is turned on;
The proposed method is to reduce the output of the inverter circuit 4 in response to a temperature rise inside the lighting equipment when the lighting is dimmed, and increase the output of the inverter circuit 4 in response to a temperature rise inside the lighting equipment when the lighting is fully lit. It will be done.

FIG. 2 shows a specific configuration of the rectifier/smoothing circuit 3 and the inverter circuit 4 in FIG. 1. In Figure 2, DB
is a diode bridge, and C1 is a smoothing capacitor, which constitute a rectifier/smoothing circuit 3. Q, , C2 are transistors, L is a choke coil, and C2 is a capacitor that forms a resonant circuit with the choke coil L.
These constitute the inverter circuit 4.

Now, in the case where the inverter circuit 4 has a circuit configuration as shown in FIG. In the resonance characteristics shown in Figure 3 (characteristics of changes in the voltage of capacitor C2 with respect to changes in the switching frequency of transistors Q, Q2), when fully lit, For example, the inverter circuit 4 operates at a switching frequency of point F, and when lighting is dimmed, the inverter circuit 4 operates at a switching frequency of point D, for example.

In the above-mentioned switching operation during full lighting and dimmed lighting, the first method is to change the switching frequency (frequency at point D) during dimmed lighting to the temperature inside the lighting equipment by the temperature detection means 8. For example, it is raised in response to detection of a rise in the tube wall temperature of the discharge lamp 5, thereby reducing the output of the inverter circuit 4 during dimming lighting, thereby reducing the light output of the discharge lamp 5. As a result, in accordance with the decrease in the light output of the discharge lamp 5 when the discharge lamp is fully lit due to a rise in temperature, the light output of the discharge lamp 5 when the discharge lamp is dimmed can be reduced in the same way, keeping the dimming ratio approximately constant. can be kept.

In addition, as a second method, the switching frequency (frequency at point F) during full lighting is lowered in response to the temperature detection means 8 detecting an increase in the temperature inside the lighting equipment, for example, the temperature of the tube wall of the discharge lamp 5. , thereby increasing the output of the inverter circuit 4 when the lamp is fully lit, thereby increasing the light output of the discharge lamp 5. As a result, the discharge lamp 5 when fully lit due to temperature rise
The decrease in optical output can be compensated for, and the dimming ratio can be kept approximately constant.

Furthermore, as a third method, a combination of the first and second methods can be considered. That is, the switching frequency (frequency at point D) during dimming lighting is increased in response to the temperature detection means 8 detecting an increase in the temperature inside the lighting equipment, for example, the tube wall temperature of the discharge lamp 5, and thereby the dimming is performed. By reducing the output of the inverter circuit 4 during lighting, the light output of the discharge lamp 5 during dimming lighting is reduced. In addition, the switching frequency (frequency at point F) when all lights are on is lowered in response to the temperature detection means 8 detecting a rise in temperature inside the lighting equipment, thereby increasing the output of the inverter circuit 4 when all lights are on. to increase the light output of the discharge lamp 5. As a result, in accordance with the decrease in the light output of the discharge lamp 5 when the discharge lamp is fully lit due to a temperature rise, the light output of the discharge lamp 5 when the discharge lamp is dimmed and lit can be reduced in the same way, and the light output of the discharge lamp 5 when the discharge lamp is fully lit can be reduced in the same way as the temperature rises. It is possible to compensate for the decrease in the light output of the discharge lamp 5 during the operation, and it is possible to keep the dimming ratio substantially constant.

As described above, by changing the oscillation frequency of the inverter circuit 4 based on the output of the temperature detection means 8, it is possible to keep the dimming ratio substantially constant regardless of changes in the internal temperature of the lighting equipment.

Although the above description has been made regarding the case where the inverter circuit 4 operates in the slow phase mode, the present invention can be similarly applied to the case where the inverter circuit 4 operates in the fast phase mode. In this case, if the relationship between the frequencies described above is just reversed, the same operation as described above will occur.

In addition, in the above explanation, the configuration is such that switching between full lighting and dimmed lighting is performed by changing the oscillation frequency, but a discharge lamp lighting device that performs dimming by changing the duty ratio of the oscillation signal may also be used. By setting the duty ratio according to the internal temperature of the lighting equipment to match the operation, the dimming ratio between full lighting and dimmed lighting can be kept approximately constant regardless of changes in the lighting equipment's internal temperature. can.

FIG. 4 shows a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention. This discharge lamp lighting device embodies an oscillation circuit 7, a temperature detection means 8, and a control circuit 9, and the other configurations are the same as in the first embodiment.

The oscillation circuit 7 is composed of a comparator IC, switching elements Q II and Q 13, and a capacitor CI+, and is configured to generate a sawtooth voltage using charging and discharging of the capacitor C11.

The temperature detection means 8 is composed of, for example, a diode, and uses the fact that the forward voltage V of the diode has temperature characteristics as shown in FIG. It is configured to detect the internal temperature of the appliance. The mounting position of the temperature detection means 8 consisting of a diode will be described later.

The control circuit 9 includes transistors Q1. , resistors RII and RI2 that determine the current flowing through the transistor Q1□, an all-lighting switch SW, and a dimming lighting switch SWD.

FIG. 6 shows a schematic sectional view of an example of a lighting fixture in the discharge lamp lighting device of this embodiment, and FIG. 7 shows a plan view of a circuit board of the lighting fixture of FIG. 6.

In FIG. 6, 31 is the instrument main body, 32 is the main body reflector,
33 is a shade, 34 is a lamp socket that also serves as a lamp holder, 35 is a lamp support spring, 36 is an annular fluorescent lamp, 3
7 is a miniature ball, and 38 is a circuit board on which various parts are mounted.

In FIG. 7, 41 is a smoothing capacitor, 42 is a resonant capacitor, 43 is the main switching element of the inverter circuit, 44 is a heat sink, 45 is a resistor, 46 is a high-print IC board, and 47 is a temperature detection device such as a diode. In the case of this figure, by attaching the main switching element 43 facing the heat radiator 44 that emits heat, the internal temperature of the lighting device is detected by receiving the radiant heat from the heat radiator 44. There is.

Next, the operation will be explained.

When all lighting switch SW is on, dimming lighting switch SWD is turned on.
When Ql! is off, transistor Ql! The current flowing through the resistor R11 is determined by the resistance value of the resistor R11. Then, a current with the same value as this current flows through the transistor Q11, and the capacitor C11 is slowly charged with the current flowing through the transistor Ql+, and the voltage across the capacitor C11 rises at a predetermined slope.The rising slope of this voltage is It is determined by the resistance value of resistor R1+.

While the voltage across the capacitor CI+ is lower than the voltage VC, the transistor Q13 is off, but when the voltage exceeds the voltage VC, the output of the comparator IC1 is inverted and the transistor Q13 is turned off.
13 is turned on, the charge of the capacitor C11 is rapidly discharged, and the voltage across the capacitor C11 becomes zero. As a result, the output of comparator IG returns to its original state and transistor Q
I3 is turned off and charging of the capacitor CI+ is restarted, and by repeating the above operation, the capacitor CI+
The voltage across the terminal changes in a sawtooth waveform. This sawtooth voltage is applied to the waveform control circuit 10, converted into, for example, a square wave voltage suitable for driving the switching elements of the inverter circuit B4, and supplied to the drive circuit 6. The resistor R is set so that the frequency of the sawtooth voltage at this time matches the switching frequency at point F in FIG.
A resistance value of 1+ is set.

On the other hand, when the full lighting switch SWF is off and the dimming lighting switch SWD is on, the current flowing through the transistor q+z is determined by the resistance value of the resistor R1 and the forward voltage vF of the diode D1. The resistance value of this resistor RI2 is determined as follows, for example, when the inverter circuit 4 is configured as shown in FIG. 2 and operated in slow phase mode, the switching frequency needs to be higher during dim lighting than when fully lit. Set it to a smaller value than the resistor R11 to increase the rising slope of the voltage across the capacitor C11, shorten the repetition period of the sawtooth voltage, and make the frequency match the switching frequency at point D in Figure 3. The resistance value of resistor R1 is set.

Since the forward voltage V of the diode D has a temperature characteristic as shown in FIG. 5, as the internal temperature of the lighting device increases, its value changes in a direction of decreasing. As a result, when the internal temperature of the lighting device rises, the forward voltage (2) of the diode D1 decreases, and the voltage applied to the resistor RH increases. As a result, the current flowing to the transistor Q1□ through the resistor RI2 increases, and therefore the current flowing to the capacitor CI+ increases. Therefore, the frequency of the sawtooth voltage during dimming lighting increases, the switching frequency of the inverter circuit 4 increases, and the output of the inverter circuit 4 during dimming lighting decreases. In other words, in accordance with the decrease in the light output of the discharge lamp 5 during full lighting due to the increase in the internal temperature of the lighting equipment, the light output of the discharge lamp 5 during dimming lighting also decreases, and the dimming ratio becomes lower than the internal temperature of the lighting equipment. It remains approximately constant regardless of changes in temperature.

FIG. 8 shows a circuit diagram of the main parts of a discharge lamp lighting device according to a third embodiment of the present invention. This discharge lamp lighting device uses a parallel circuit of a diode D1 and a resistor RI3 as the temperature detection means 8', and the other configuration is the same as that in FIG. 4.

In the one in Figure 4, the temperature characteristic is that of diode D.

It is uniquely determined by the temperature characteristics of the forward voltage (■), but as shown in FIG.
3 are connected in parallel, the temperature characteristics can be adjusted by changing the resistance value of the resistor RI3. In the case of this circuit, if the change in the switching frequency with respect to temperature change is too large based on only the temperature characteristics of the forward voltage (2) of the diode D1, the change in the switching frequency can be suppressed by the resistor RI3. That is, the eighth
In the case of the circuit shown in the figure, the switching frequency during dimming lighting is such that the combined current of the current flowing to the resistor RH through the diode D1 and the current flowing to the resistor R1 through the resistor R13 flows through the transistor QH, and the lighting equipment. When the internal temperature rises, resistance RI2 increases through diode D1.
The same current flows as in the case of Figure 4, but since the current simultaneously flows through resistor RI2 through resistor RI3, which has no temperature characteristics, the current change due to temperature change in the composite current is the same as in the case of diode D1 alone. It becomes smaller than .

As described above, since the resistor RI3 is provided in parallel with the diode D1, by changing the resistor RI3 for each lighting fixture, it is easy to change the characteristics according to the difference in internal temperature rise due to different lighting fixtures. It can be adjusted optimally for each type of lighting equipment.

Other configurations and effects are the same as those in FIG. 4.

In each of the above embodiments, the output of the inverter circuit 4 is changed using the temperature characteristics of the forward voltage of the diode D1, but a resistor having temperature characteristics such as a thermistor may be used instead of the diode D1. You can also do it.

FIG. 9 shows a circuit diagram of the main parts of a discharge lamp lighting device according to a fourth embodiment of the present invention. This discharge lamp lighting device shows an embodiment in which the output of the inverter circuit during full lighting is increased as the internal temperature of the lighting fixture increases.

In FIG. 9, only the oscillation circuit 7', the temperature detection means 8, and the control circuit 9' are shown. Other parts are the same as those shown in FIG.

The oscillation circuit 7' is a general-purpose timer circuit (for example, μPCl5
55. (manufactured by NEC)■C2 and its associated resistance R
14, RI5, capacitor CI! It consists of

The control circuit 9' includes resistors RI6. R87, R1s, total 6.
It is composed of a switch SW, and a dimmer lighting switch SWo.

The temperature detection means 8 is the same as that shown in FIG.

Next, the operation will be explained.

The oscillation circuit 7' includes resistors R14, RR5, and capacitor CD.
A charging circuit is constituted by R15, a discharging circuit is constituted by capacitors C and 2, and a triangular wave voltage is generated by this and a general-purpose timer circuit IC2. The 5th terminal of the general-purpose timer circuit C2 switches between charging and discharging in the same way as the comparator C1 in FIG. The charging and discharging of the capacitor C1□ is switched using the divided voltage of .

When fully lit, the diode D2. A circuit consisting of a resistor R16, a switch SW, and a resistor RI8 generates the switching frequency1, and for dimming lighting, the resistor R3
7. A switching frequency is generated by a circuit composed of a switch SWD and a resistor R18.

The third terminal of the general-purpose timer circuit ■C2 is an oscillation output terminal.

The temperature detection means 8 consisting of the diode D1 has temperature characteristics as shown in FIG.

When the temperature rises, the forward voltage VF of the diode D2 decreases with respect to the voltage at the No. 5 terminal of the general-purpose timer circuit IC2, which is set at room temperature. In this case, the voltage (voC-VF)
Since the voltage is divided by the resistor R16 and the resistor R18, the voltage at the No. 5 terminal is higher than that at room temperature. As a result, the frequency decreases and the light output increases.

During dimming lighting, the partial voltage is applied to resistor RI7. Since this is done with RII1, even if the temperature changes, the divided voltage does not change, and therefore the frequency does not change either.

As described above, in this embodiment, the output of the inverter circuit 4 is increased in response to a rise in the internal temperature of the lighting device when the lighting device is fully lit, so even if the internal temperature of the lighting device changes, the dimming ratio is can be kept approximately constant. In addition, since the change in light output due to temperature rise inside the lighting equipment is large when the lighting is fully lit, if the dimming ratio is kept approximately constant by increasing the output when the lighting is fully lit, the light intensity of the discharge lamp 5 The temperature itself can also be maintained substantially constant regardless of temperature changes within the lighting equipment.

〔Effect of the invention〕

According to the discharge lamp lighting device according to claim 11, since the oscillation state of the inverter circuit is controlled according to the output of the temperature detection means, the oscillation state of the inverter circuit is controlled according to the output of the temperature detection means, so that the oscillation state of the inverter circuit is controlled depending on the temperature change within the lighting equipment. Even if the luminous efficiency of the discharge lamp changes, the output of the inverter circuit can be changed accordingly, and the dimming ratio of the discharge lamp can be kept substantially constant.

According to the discharge lamp lighting device according to claim (2), the output of the inverter circuit during dimming lighting is reduced in response to a temperature rise within the lighting equipment, thereby keeping the dimming ratio of the discharge lamp substantially constant. can be kept.

According to the discharge lamp lighting device according to claim (3), the output of the inverter circuit during full lighting is increased in response to a temperature rise within the lighting equipment, thereby keeping the dimming ratio of the discharge lamp substantially constant. be able to. In this case, the change in light output due to temperature rise inside the lighting equipment is large when it is fully lit, so if the dimming ratio is kept approximately constant by increasing the output when fully lit, the light output of the discharge lamp The temperature itself can also be maintained substantially constant regardless of temperature changes within the lighting equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a discharge lamp lighting device according to a first embodiment of the present invention, FIG. 2 is a circuit diagram showing the specific configuration of the main parts of FIG. 1, and FIG. 3 is a capacitor of a resonant circuit. FIG. 4 is a circuit diagram showing the configuration of a discharge lamp lighting device according to a second embodiment of the present invention, FIG. 5 is a temperature characteristic diagram of forward voltage of a diode, and FIG. The figure is a sectional view of the lighting fixture, Figure 7 is a plan view of the circuit board built into the lighting fixture of Figure 6, and Figure 8 is the third embodiment of the invention.
9 is a main circuit diagram showing the structure of a fourth embodiment of the present invention, FIG. 10 is a temperature characteristic diagram of luminous efficiency of a discharge lamp, and FIG. 11 is a main circuit diagram showing the structure of a fourth embodiment of the present invention. and the twelfth
The figure is a time chart showing changes in the light output of the discharge lamp. l...DC power supply, 4...inverter circuit, 5...
Discharge lamp, 8... Temperature detection means 9... Control circuit 3 Threshold chart ηi Fig. Fig. 7 Fig. 7 6

Claims (3)

[Claims] (1) a DC power supply, an inverter circuit that converts the voltage of the DC power supply into a high-frequency voltage, a discharge lamp that is lit by being supplied with power from the inverter circuit, a temperature detection means that detects the temperature inside the lighting equipment; By controlling the oscillation state of the inverter circuit, the discharge lamp is switched between full lighting and dimmed lighting, and the output of the inverter circuit is changed by controlling the oscillation state of the inverter circuit according to the output of the temperature detection means. A discharge lamp lighting device comprising a control circuit that controls the operation of the discharge lamp. (2) The discharge lamp lighting device according to claim (1), wherein the control circuit is configured to reduce the output of the inverter circuit during dimming lighting in response to a rise in temperature within the lighting fixture. (3) The discharge lamp lighting device according to claim (1), wherein the control circuit increases the output of the inverter circuit during full lighting in response to a rise in temperature within the lighting fixture.