Lighting device for discharge lamp and irradiation device

Abstract

To provide a lighting device for a discharge lamp and an irradiation device that can save energy and can perform appropriate lighting.SOLUTION: A lighting device applies drive voltage at a predetermined frequency to a hot-cathode discharge lamp, and is provided with: an inverter circuit; a resonance circuit having a first resonance circuit that is connected, on an input side, with an output side of the inverter circuit and connected, on an output side, with a pair of electrodes of the hot-cathode discharge lamp, and resonates lamp current, and a second resonance circuit that resonates filament current flowing in the electrodes; a switching circuit that is connected between the second resonance circuit and the electrodes, and switches between application of the filament current and stop of the application; and a control circuit that controls the switching circuit. At least one of before lighting and at start-up, the control circuit executes the application of the filament current, and after the start-up, selects and executes one of the application of the filament current and the stop of the application on the basis of input data of the hot-cathode discharge lamp.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present invention relates to a discharge lamp lighting device and an irradiation device. [Background technology]

[0002] There is a lighting device that lights a hot cathode discharge lamp. If the lighting device is used to light the hot cathode discharge lamp at the same time as starting the lamp, the lamp will start to light while the electrodes of the hot cathode discharge lamp are still in a low temperature state. In such a case, a glow discharge will occur near the electrodes of the hot cathode discharge lamp, and then an arc discharge will start. Since the electrodes of a hot cathode discharge lamp are designed to maintain an arc discharge at a high temperature, if a glow discharge is caused at the electrodes in a low temperature state during starting, the life of the hot cathode discharge lamp will be shortened.

[0003] For this reason, the lighting device passes a predetermined current through the electrodes before or at the start of lighting, causing the electrodes to heat up. For example, before or at the start of lighting, a current is passed through the electrodes for about 2 seconds, causing the electrodes to heat up (preheat). In this case, the lighting device can continue to pass the current passed during preheating even after starting, in order to keep the temperature of the electrodes within an appropriate range.

[0004] Also, in order to save energy, lighting devices have been proposed that reduce the current flowing through the electrodes or stop the current flowing through the electrodes after startup.

[0005] However, simply stopping the flow of current to the electrodes after startup may result in the temperature of the electrodes being outside of the appropriate range after startup. Therefore, there has been a demand for development of a technology that can save energy and provide appropriate lighting. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-351790 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a discharge lamp lighting device and an irradiation device that can save energy and perform appropriate lighting. [Means for solving the problem]

[0008] A discharge lamp lighting device according to an embodiment is a lighting device that applies a drive voltage of a predetermined frequency to a hot cathode discharge lamp. The discharge lamp lighting device includes an inverter circuit; a resonant circuit having an input side electrically connected to an output side of the inverter circuit and an output side electrically connected to a pair of electrodes of the hot cathode discharge lamp, the resonant circuit having a first resonant circuit for resonating a lamp current flowing through the hot cathode discharge lamp and a second resonant circuit for resonating a filament current flowing through the electrodes; a switching circuit electrically connected between the second resonant circuit and the electrodes, for switching between application of the filament current and stopping of application of the filament current; and a control circuit for controlling the switching circuit. The control circuit controls the switching circuit to apply the filament current at least either before lighting begins or during startup. After startup, the control circuit controls the switching circuit based on input data of the hot cathode discharge lamp to selectively apply the filament current and stop application of the filament current. Effect of the Invention

[0009] According to the embodiments of the present invention, it is possible to provide a discharge lamp lighting device and an irradiation device that can achieve energy saving and perform appropriate lighting. [Brief description of the drawings]

[0010] [Figure 1]1 is a circuit diagram illustrating an irradiation device including a discharge lamp lighting device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate. There are no particular limitations on the uses of the discharge lamp lighting device according to this embodiment, and it can be used as an irradiation device (lighting device) equipped with a hot cathode discharge lamp that irradiates visible light, an irradiation device (ultraviolet irradiator) equipped with a hot cathode discharge lamp that irradiates ultraviolet light, etc.

[0012] FIG. 1 is a circuit diagram illustrating an irradiation device 100 including a discharge lamp lighting device 1 according to the present embodiment. As shown in FIG. 1, the irradiation device 100 includes a hot cathode discharge lamp 101 and a discharge lamp lighting device 1 (hereinafter simply referred to as lighting device 1).

[0013] The hot cathode discharge lamp 101 has, for example, an arc tube 101a and an electrode 101b. The arc tube 101a has, for example, a cylindrical shape. The arc tube 101a is formed from a material that transmits visible light and ultraviolet light and has heat resistance. The arc tube 101a is formed from, for example, quartz, glass, or the like. Both ends of the arc tube 101a are sealed. A discharge medium is enclosed in the internal space of the arc tube 101a. The discharge medium is, for example, a rare gas and mercury, or a rare gas and an amalgam. The rare gas can be, for example, a single gas such as argon gas or xenon gas, or a mixed gas in which multiple types of rare gases are mixed. The gas pressure (enclosed pressure) in the internal space of the arc tube 101a at 25° C. is, for example, about 1 Torr (133.322 Pa) to 10 Torr (1333.22 Pa). The enclosed pressure can be determined based on the standard state of gas (SATP (Standard Ambient Temperature and Pressure): temperature 25° C., 1 bar). The enclosed amount of mercury or amalgam is, for example, about 1 mg to 10 mg. When the hot cathode discharge lamp 101 is used in a lighting device, for example, a layer containing a phosphor that converts ultraviolet light into visible light can be provided on the inner wall of the arc tube 101a.

[0014] The electrodes 101b are provided at both ends of the arc tube 101a, and each electrode 101b has a lead 101b1 and a filament 101b2. A pair of leads 101b1 are provided for each electrode 101b. The pair of leads 101b1 are held in the sealed portions at the ends of the arc tube 101a. The leads 101b1 are linear. One end of the lead 101b1 is exposed to the internal space of the arc tube 101a. The other end of the lead 101b1 is exposed to the outside of the arc tube 101a. The filament 101b2 is provided in the internal space of the arc tube 101a. The filament 101b2 is held by a pair of leads 101b1 in the internal space of the arc tube 101a. The filament 101b2 is formed, for example, by winding a wire in a spiral shape. The wire contains, for example, tungsten or a rhenium-tungsten alloy.

[0015] The filament 101b2 holds an emitter containing, for example, a mixture of BaO, SrO, and CaO. A ribbon containing, for example, a mercury alloy (for example, a mercury-titanium alloy), zirconium, aluminum, or the like can also be joined to the filament 101b2.

[0016] Here, when high-frequency power is applied to one electrode 101b (cathode) by the lighting device 1 described later, the filament 101b2 is heated. Then, thermoelectrons are emitted from the emitter held by the filament 101b2, which is heated to about 600°C to 1100°C. The emitted electrons move to the other electrode 101b (anode) side, causing a discharge. The emitted electrons collide with mercury atoms enclosed in the internal space of the arc tube 101a. When the electrons collide with the mercury atoms, the mercury atoms receive the energy of the electrons, and ultraviolet rays with a peak wavelength of about 254 nm are generated. The generated ultraviolet rays are irradiated to the outside of the arc tube 101a. Note that, when the hot cathode discharge lamp 101 irradiates visible light, the generated ultraviolet rays are converted to visible light by a layer containing a phosphor provided on the inner wall of the arc tube 101a, and the converted visible light is irradiated to the outside of the arc tube 101a.

[0017] An irradiation device (ultraviolet irradiation device) equipped with a lighting device 1 and a hot cathode discharge lamp 101 that irradiates ultraviolet rays can be used, for example, to harden or dry resins or inks applied to an object, modify the surface of an object, decompose foreign matter attached to the surface of an object, sterilize bacteria or inactivate viruses in the air or attached to the surface of an object, etc. Moreover, an irradiation device (illumination device) including the lighting device 1 and a hot cathode discharge lamp 101 that irradiates visible light can be used for general illumination, backlighting, and the like.

[0018] The hot cathode discharge lamp 101 is electrically connected to the output side of the lighting device 1. The hot cathode discharge lamp 101 can be detachably mounted in a socket or the like provided in the lighting device 1, for example.

[0019] The lighting device 1 applies to the hot cathode discharge lamp 101 a drive voltage of a predetermined frequency. As shown in FIG. 1, a lighting device 1 includes, for example, a filter circuit 2, a rectifier circuit 3, a power factor correction circuit 4, an inverter circuit 5, a resonance circuit 6, a switching circuit 7, and a control circuit 8.

[0020] The input side of the filter circuit 2 is electrically connected to the power source 200. The power source 200 can be, for example, a commercial power source (AC power source). The power source 200 may be a DC power source. The DC power source is, for example, a DC power source that converts AC to DC, a battery, or the like. When the power source 200 is a DC power source, for example, the rectifier circuit 3 can be omitted.

[0021] The filter circuit 2, for example, suppresses noise generated in the inverter circuit 5 from leaking out of the lighting device 1. The filter circuit 2 also suppresses noise from entering the lighting device 1 from the outside. There are no particular limitations on the circuit configuration of the filter circuit 2. For example, the filter circuit 2 may include a choke coil and a capacitor.

[0022] The input side of the rectifier circuit 3 is electrically connected to the output side of the filter circuit 2. The rectifier circuit 3 converts the AC voltage from the power source 200 into a DC voltage. The rectifier circuit 3, for example, full-wave rectifies the AC voltage from the power source 200. There is no particular limitation on the circuit configuration of the rectifier circuit 3. The rectifier circuit 3 can be, for example, a diode bridge circuit.

[0023] The input side of the power factor correction circuit 4 is electrically connected to the output side of the rectifier circuit 3. The power factor correction circuit 4 reduces the phase difference between the input voltage and the output current to bring the power factor closer to 1. There are no particular limitations on the circuit configuration of the power factor correction circuit 4. The power factor correction circuit 4 may be, for example, any of a passive type power factor correction circuit, a partial switching type power factor correction circuit, and a switching type (active type) power factor correction circuit.

[0024] The input side of the inverter circuit 5 is electrically connected to the output side of the power factor correction circuit 4. The inverter circuit 5 converts the DC voltage converted by the rectifier circuit 3 into an AC voltage of a predetermined frequency by PWM (Pulse Width Modulation) control. In this case, the frequency is, for example, about 30 kHz to 300 kHz. As shown in FIG. 1, for example, the inverter circuit 5 can be a half-bridge circuit using a switching element 5a such as a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). Note that the inverter circuit 5 may be a full-bridge circuit using the switching element 5a.

[0025] The inverter circuit 5 applies a voltage (lamp voltage) between a pair of filaments 101b2 provided in the hot cathode discharge lamp 101, and causes a current (lamp current) to flow, thereby lighting the hot cathode discharge lamp 101. The inverter circuit 5 fixes the ratio between a period (on period) during which the lamp current flows through the hot cathode discharge lamp 101 and a period (off period) during which the lamp current does not flow through the hot cathode discharge lamp 101, and changes the frequency of the lamp current (lamp voltage) during the on period, thereby changing the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101. By lowering the frequency of the lamp current (lamp voltage), the lamp current increases, and the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 can be increased. By increasing the frequency of the lamp current (lamp voltage), the lamp current decreases, and the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 can be reduced.

[0026] Furthermore, the inverter circuit 5 can change the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 by changing the ratio of a period (on period) during which the lamp current flows through the hot cathode discharge lamp 101 to a period (off period) during which the lamp current does not flow through the hot cathode discharge lamp 101 while keeping the frequency of the lamp current (lamp voltage) approximately constant. Increasing the ratio of the on period increases the lamp current, and the intensity of the ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 can be increased. Reducing the ratio of the on period decreases the lamp current, and the intensity of the ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 can be reduced. That is, the inverter circuit 5 can also perform burst dimming by PWM control. The operation of the inverter circuit 5 as described above can be controlled by a control circuit 8 which will be described later.

[0027] Here, when starting (when power is turned on), the temperature of the filament 101b2 is low. Therefore, when a driving voltage of a predetermined frequency is applied to the hot cathode discharge lamp 101 at the same time as starting, lighting begins with the filament 101b2 still in a low temperature state. In such a case, first, a glow discharge occurs in the vicinity of the filament 101b2. Then, an arc discharge occurs between the filaments 101b2, and ultraviolet rays are generated throughout the entire area of ​​the hot cathode discharge lamp 101.

[0028] However, since the electrodes 101b (filament 101b2, emitter, ribbon) of the hot cathode discharge lamp 101 are designed to maintain an arc discharge at a high temperature, if a glow discharge is generated at the electrodes 101b in a low temperature state during startup, the life of the hot cathode discharge lamp 101 (electrodes 101b) will be shortened.

[0029] Therefore, the inverter circuit 5 flows a predetermined current through the electrode 101b (filament 101b2) before lighting begins and / or during startup, to heat (preheat) the filament 101b2. For example, the inverter circuit 5 applies a voltage to the electrode 101b of the hot cathode discharge lamp 101 at a frequency higher than the frequency during lighting and lower than the voltage required for startup, at least either before lighting begins and / or during startup. The application time is, for example, about 2 seconds. In this way, it is possible to suppress the occurrence of glow discharge, and to pass a filament current through the filament 101b2 to heat the filament 101b2. If the filament 101b2 generates heat, the temperature of the electrode 101b can be made to be suitable for lighting.

[0030] The input side of the resonant circuit 6 is electrically connected to the output side of the inverter circuit 5. The output side of the resonant circuit 6 is electrically connected to a pair of electrodes 101b (filament 101b2) of the hot cathode discharge lamp 101.

[0031] As shown in FIG. 1, the resonant circuit 6 includes a capacitor 6a, a transformer 6b, and a capacitor 6c. The capacitor 6a is electrically connected between the output side of the inverter circuit 5 and the primary winding of the transformer 6b. In this case, the capacitor 6a and the transformer 6b form an LLC resonant circuit (corresponding to an example of a first resonant circuit). That is, the lighting device 1 includes a series resonant inverter in which the inverter circuit 5 and a resonant circuit 6 having an LLC resonant circuit are connected in series. The LLC resonant circuit having the capacitor 6a and the transformer 6b is a resonant circuit that resonates the lamp current flowing between the filaments 101b2 of the hot cathode discharge lamp 101. That is, the lighting device 1 controls the lamp current by the inverter circuit 5 and the LLC resonant circuit having the capacitor 6a and the transformer 6b.

[0032] Also, a pair of capacitors 6c may be provided. Each of the pair of capacitors 6c is electrically connected between the secondary winding of the transformer 6b and the electrode 101b (filament 101b2) of the hot cathode discharge lamp 101. In this case, the capacitor 6c and the transformer 6b form an LC resonant circuit (corresponding to an example of a second resonant circuit). The LC resonant circuit having the capacitor 6c and the transformer 6b is a resonant circuit that resonates a current (filament current) flowing through the filament 101b2 when the filament 101b2 is heated. That is, the lighting device 1 controls the filament current by the inverter circuit 5 and the LC resonant circuit having the capacitor 6c and the transformer 6b.

[0033] The inverter circuit 5 can change the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 by fixing the ratio between the period during which lamp current flows through the hot cathode discharge lamp 101 (on period) and the period during which lamp current does not flow through the hot cathode discharge lamp 101 (off period) and changing the frequency of the lamp current (lamp voltage) during the on period. In this case, the inverter circuit 5 can increase the lamp current and reduce the filament current by lowering the frequency of the voltage applied to the hot cathode discharge lamp 101 during the on-period. On the other hand, the inverter circuit 5 can decrease the lamp current and increase the filament current by raising the frequency of the voltage applied to the hot cathode discharge lamp 101 during the on-period.

[0034] The inverter circuit 5 can also change the intensity of ultraviolet light or visible light irradiated from the hot cathode discharge lamp 101 by changing the ratio of a period during which a lamp current flows through the hot cathode discharge lamp 101 (on period) to a period during which a lamp current does not flow through the hot cathode discharge lamp 101 (off period). That is, the inverter circuit 5 can perform burst dimming by PWM control.

[0035] The switching circuit 7 is electrically connected between the LC resonant circuit of the resonant circuit 6 and the electrode 101b of the hot cathode discharge lamp 101. For example, the switching circuit 7 is electrically connected between the secondary winding of the transformer 6b and the electrode 101b (filament 101b2) of the hot cathode discharge lamp 101. The switching circuit 7 switches between application of the lamp current to the filament 101b2 and stopping of the application of the lamp current. The switching circuit 7 may be, for example, a relay circuit. The switching circuit 7 may have, for example, a triac 7a. The switching circuit 7 is not limited to having a triac 7a, and may be any circuit capable of switching between application and stopping of the lamp current. For example, the switching circuit 7 may be a circuit in which a pair of thyristors are connected in inverse parallel to allow a current to flow in both directions.

[0036] The control circuit 8 is electrically connected to the inverter circuit 5 and the switching circuit 7. The control circuit 8 generates, for example, a PWM signal and inputs it to the switching element 5a of the inverter circuit 5. That is, the control circuit 8 inputs the generated PWM signal to the switching element 5a of the inverter circuit 5, thereby causing a lamp current to flow through the hot cathode discharge lamp 101 and lighting the hot cathode discharge lamp 101. As described above, the control circuit 8 can also perform burst dimming by changing the ratio between the on period and the off period. Moreover, the control circuit 8 controls the switching circuit 7 to apply the above-mentioned filament current to the filament 101b2 or to stop the application of the filament current.

[0037] As described above, the filament current is applied to the filament 101b2 at least either before the start of lighting or during startup. In this case, after startup, the control circuit 8 can control the switching circuit 7 to stop the filament current from being applied to the filament 101b2. In this way, the power consumption can be reduced by the amount of the filament current not being applied to the filament 101b2 after the hot cathode discharge lamp 101 is started. In other words, energy saving in the irradiation device 100 can be achieved.

[0038] However, as described above, after the hot cathode discharge lamp 101 starts, there are an on-period during which the lamp current flows and an off-period during which the lamp current does not flow. Therefore, if the application of the filament current is simply stopped after the hot cathode discharge lamp 101 starts, the temperature of the filament 101b2 may drop too much during the off-period. If the temperature of the filament 101b2 drops during the off-period, when the lamp current flows through the filament 101b2, which has a low temperature, during the on-period, the emission of thermoelectrons from the emitter provided in the filament 101b2 may become insufficient, and the filament 101b2 may be sputtered. When the filament 101b2 is sputtered, the emitter is scattered and sputtered, so that the life of the filament 101b2 and the life of the hot cathode discharge lamp 101 may be shortened due to the consumption of the emitter. That is, if the application of the filament current is simply stopped after the hot cathode discharge lamp 101 is started in order to save energy, a new problem arises in that the life of the hot cathode discharge lamp 101 is shortened.

[0039] As a result of investigation, the present inventors have found that, depending on the specifications of the hot cathode discharge lamp 101, it is possible to suppress a drop in the temperature of the filament 101b2 during the off period even if the application of the filament current is stopped after starting.

[0040] For example, when the light-emitting length (the distance between a pair of filaments 101b2) of the hot cathode discharge lamp 101 is 80 cm or more and the rated power (input power) is at least one of 120 W or more and 320 W or less, the size of the filament 101b2 (the heat capacity of the filament 101b2) can be made large, thereby preventing the temperature of the filament 101b2 from dropping excessively during the off period.

[0041] Therefore, in the lighting device 1 according to this embodiment, the control circuit 8 controls the switching circuit 7 to apply the filament current at least either before lighting begins or during startup. After startup, the control circuit 8 controls the switching circuit 7 based on the input data of the hot cathode discharge lamp 101 to selectively apply the filament current or stop the application of the filament current. For example, when the input data of the hot cathode discharge lamp 101 indicates that the light-emitting length of the hot cathode discharge lamp 101 is 80 cm or more and that the rated power is 120 W or more and 320 W or less, the control circuit 8 selects and executes the stop of the application of the filament current after starting. Also, when the input data of the hot cathode discharge lamp 101 indicates "stop of application of the filament current", the control circuit 8 selects and executes the stop of application of the filament current after starting. In this case, the "stop of application of the filament current" is determined by the operator based on the light-emitting length and rated power of the hot cathode discharge lamp 101. Therefore, the light-emitting length and rated power of the hot cathode discharge lamp 101 are indirectly input to the control circuit 8.

[0042] 1, an input unit 8a can be electrically connected to the control circuit 8. The input unit 8a may be provided integrally with the control circuit 8, or may be electrically connected to the control circuit 8 via, for example, a LAN (Local Area Network) or the like.

[0043] The input unit 8a can input data of the hot cathode discharge lamp 101 mounted on the lighting device 1. The data of the hot cathode discharge lamp 101 input to the input unit 8a includes the light emission length, rated power, model number, and whether or not the application of the filament current needs to be stopped. The data of the hot cathode discharge lamp 101 may be input to the input unit 8a by an operator, or may be input to the input unit 8a by a control device provided outside the irradiation device 100 via a LAN or the like. In addition, the operator may use the input unit 8a to select a corresponding item from a recipe input in advance to the control circuit 8. In addition, when the data of the hot cathode discharge lamp 101 input to the input unit 8a is whether or not the application of the filament current needs to be stopped, the input unit 8a may be an ON / OFF switch that selects "stopping application of the filament current" or "applying the filament current".

[0044] The control circuit 8 judges whether to apply a filament current or not to apply a filament current after starting the hot cathode discharge lamp 101 based on the data of the hot cathode discharge lamp 101 input to the input unit 8a. Based on the judgment result, the control circuit 8 selectively applies the filament current or stops the application of the filament current.

[0045] For example, when the rated power of the hot cathode discharge lamp 101 input to the input unit 8a is less than 120 W, the control circuit 8 applies a filament current to the filament 101b2 even after starting the hot cathode discharge lamp 101. For example, when the rated power of the hot cathode discharge lamp 101 input to the input unit 8a is 120 W or more, the control circuit 8 does not apply a filament current to the filament 101b2 after starting the hot cathode discharge lamp 101.

[0046] In this way, it is possible to conserve energy in the irradiation device 100. In addition, since it is possible to prevent the temperature of the filament 101b2 from dropping excessively during the off period, the life of the filament 101b2 is shortened, and the hot cathode discharge lamp 101 can be appropriately lit.

[0047] Although some embodiments of the present invention have been illustrated above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. In addition, the above-mentioned embodiments can be implemented in combination with each other.

[0048] Below, supplementary notes regarding the above-described embodiment are given.

[0049] (Appendix 1) A lighting device that applies a drive voltage of a predetermined frequency to a hot cathode discharge lamp, An inverter circuit; a resonant circuit having an input side electrically connected to an output side of the inverter circuit and an output side electrically connected to a pair of electrodes of the hot cathode discharge lamp, the resonant circuit including a first resonant circuit for resonating a lamp current flowing through the hot cathode discharge lamp, and a second resonant circuit for resonating a filament current flowing through the electrodes; a switching circuit electrically connected between the second resonant circuit and the electrode, the switching circuit switching between application of the filament current and stopping application of the filament current; A control circuit for controlling the switching circuit; Equipped with The control circuit includes: At least one of before the start of lighting and during startup, controlling the switching circuit to apply the filament current; After startup, the discharge lamp lighting device controls the switching circuit based on input data for the hot cathode discharge lamp to selectively apply the filament current or stop applying the filament current.

[0050] (Appendix 2) When the input data of the hot cathode discharge lamp is at least one of the following: the light-emitting length of the hot cathode discharge lamp is 80 cm or more, and the rated power is 120 W or more and 320 W or less, 2. The discharge lamp lighting device according to claim 1, wherein the control circuit selects and executes stopping of the application of the filament current after the startup.

[0051] (Appendix 3) 3. The discharge lamp lighting device according to claim 1, wherein the second resonant circuit is an LC resonant circuit.

[0052] (Appendix 4) 4. The discharge lamp lighting device according to claim 1, further comprising an input unit electrically connected to the control circuit for inputting the data of the hot cathode discharge lamp.

[0053] (Appendix 5) Hot cathode discharge lamps; A discharge lamp lighting device according to any one of appendices 1 to 4, which is electrically connected to the hot cathode discharge lamp; An irradiation device equipped with: [Explanation of symbols]

[0054] 1 lighting device, 5 inverter circuit, 6 resonance circuit, 7 switching circuit, 8 control circuit, 8a input section, 100 irradiation device, 101 hot cathode discharge lamp, 101b electrode, 101b2 filament, 200 power supply

Claims

1. A lighting device that applies a drive voltage of a predetermined frequency to a hot cathode discharge lamp, An inverter circuit; a resonant circuit having an input side electrically connected to an output side of the inverter circuit and an output side electrically connected to a pair of electrodes of the hot cathode discharge lamp, the resonant circuit resonating a lamp current flowing through the hot cathode discharge lamp, and a second resonant circuit resonating a filament current flowing through the electrodes; a switching circuit electrically connected between the second resonant circuit and the electrode, the switching circuit switching between application of the filament current and stopping application of the filament current; A control circuit for controlling the switching circuit; Equipped with The control circuit includes: At least one of before the start of lighting and during startup, controlling the switching circuit to apply the filament current; After startup, the discharge lamp lighting device controls the switching circuit based on input data for the hot cathode discharge lamp to selectively apply the filament current or stop applying the filament current.

2. When the input data of the hot cathode discharge lamp is at least one of the following: the light-emitting length of the hot cathode discharge lamp is 80 cm or more, and the rated power is 120 W or more and 320 W or less, 2. The discharge lamp lighting device according to claim 1, wherein the control circuit selects and executes the stopping of the application of the filament current after the startup.

3. 3. The discharge lamp lighting device according to claim 1, wherein the second resonant circuit is an LC resonant circuit.

4. 3. The discharge lamp lighting device according to claim 1, further comprising an input section electrically connected to said control circuit, for inputting said data of said hot cathode discharge lamp.

5. a hot cathode discharge lamp; a discharge lamp lighting device according to claim 1, electrically connected to said hot cathode discharge lamp; An irradiation device equipped with:

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