JP2006040855A - Discharge lamp lighting device, lighting apparatus, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of controlling light of a discharge lamp to an optical output of less than 25% of rating, in which a lamp current is remarkably reduced in accordance with the thermal characteristics of the discharge lamp or the lighting device when the light of the discharge lamp is controlled, thereby preventing the occurrence of malfunctions such as flickers or fading. <P>SOLUTION: The discharge lamp lighting device comprises lighting means 2 capable of controlling the light of a discharge lamp 19 to less than 25% of the rating output, discharge lamp detection means 4 for detecting electrical parameters of the discharge lamp 19 in lit condition, and lighting control means 3 for controlling an output of the lighting means 2 according to the electrical parameters detected by the discharge lamp detection means 4 and a light control signal, wherein the discharge lamp detection means 4 detects the electrical parameters for detecting the lighting condition from two places or more when the light is controlled, and the lighting control means 3 controls the lighting means 2 based on the parameters detected from the two places or more and the light control signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a discharge lamp lighting device capable of dimming a discharge lamp, an illumination device including the discharge lamp lighting device and the discharge lamp, and an illumination system for controlling a plurality of illumination devices.

  Conventionally, as a discharge lamp lighting device capable of dimming lighting, there is one shown in FIG. This discharge lamp lighting device includes an AC-DC converter 110 composed of a diode bridge 101, a step-up chopper circuit 102, and an electrolytic capacitor 103 for accumulating the output voltage, a half-bridge inverter 104 connected to the output side thereof, and a switching signal thereof. Flows into the half bridge inverter 104, the LC resonance circuit 106 connected to the midpoint of the half bridge inverter 104, the dimming signal circuit 107 that inputs an external dimming signal to the control unit 105, and the half bridge inverter 104. A fixed resistor 108 that converts current into voltage and inputs the voltage to the control unit 105 and a discharge lamp (hereinafter referred to as a discharge lamp) 109 connected to the LC resonance circuit 106 are provided.

  In this case, the lighting means is the AC-DC converter 110, the half-bridge inverter 104, and the LC resonance circuit 106, the lighting control means is the control unit 105, and the discharge lamp detection means is the fixed resistor 108.

  Next, the operation of the discharge lamp lighting device will be described. The DC voltage obtained by the AC-DC converter 110 is converted to a high-frequency rectangular wave voltage by the high-frequency switching operation of the half-bridge inverter 104 connected to both ends thereof, and is output to the midpoint of the half-bridge. When this rectangular wave voltage is input to the LC resonance circuit 106, a substantially sinusoidal voltage is generated due to a resonance action and applied to both ends of the discharge lamp 109, and the discharge lamp 109 is lit. At this time, the source current of the half-bridge inverter 104 is converted into a voltage by the fixed resistor 108 and fed back to the control unit 105. In the control unit 105, the switching signal is controlled so that the fed back voltage has a magnitude corresponding to the dimming signal input from the dimming signal circuit 107. Thus, the output power of the discharge lamp 109 that is lit is controlled to be substantially constant.

  At this time, a discharge lamp having a VI characteristic such that the impedance of the discharge lamp is increased in a region where the lamp current is small and the impedance of the discharge lamp is increased in a lower temperature environment. When full lighting and dimming lighting are performed, the lamp current and lamp voltage of the discharge lamp are as shown in the graph of FIG.

  For example, under the conditions of dimming lighting and lamp power Wla: 7.0 W in the graph, the lighting state in the 0 ° C. environment is about 25% lower in lamp current than the lighting state in the 25 ° C. environment. However, the illuminance will decrease and the risk of flickering and disappearing will increase. Such a tendency becomes more conspicuous as the lamp output is suppressed, that is, the deep light control is performed and the temperature difference in the surrounding environment is larger. Such a tendency becomes more conspicuous as the lamp output is suppressed, that is, as the dimming control is performed deeper and the degree of the ambient environment is larger.

  Another discharge lamp lighting device capable of dimming and lighting is described in Japanese Patent Laid-Open No. 2003-77696. As shown in FIG. 12, the discharge lamp lighting device includes a DC power supply unit 202, an inverter unit 203, a load circuit unit 204, a control unit 205, and a dimming signal generation unit 206. The load circuit unit 204 includes a series resonant circuit including an inductor L2 and a capacitor C4 connected between output terminals of the inverter unit 203, and a discharge lamp La connected in parallel to the capacitor C4. Is converted into a DC voltage by the DC power supply unit 202, and further converted into a high-frequency AC voltage by the inverter unit 203 and supplied to the discharge lamp La.

That is, the inverter unit 203 converts the output of the DC power supply unit 202 into a high-frequency AC voltage and outputs it to the discharge lamp La. The dimming state detection unit 207 detects a lighting state of the discharge lamp La by detecting a signal whose signal level changes according to the dimming level of the discharge lamp La, for example, a lamp voltage. The dimming signal limiting unit 208 normally outputs the dimming signal S input from the dimming signal generation unit 206 to the control unit 205 as it is, but the dimming of the discharge lamp La detected by the dimming state detection unit 207 is performed. When the level becomes darker than the predetermined lower limit level, the value of the dimming signal S is limited to a value corresponding to the lower limit level and is output to the control unit 205. However, even in the above configuration, for example, a decrease in the ambient temperature When the discharge lamp voltage increases and the discharge lamp current decreases, the lighting state becomes unstable, and the discharge lamp may flicker or go out.
Japanese Patent Laid-Open No. 2003-77696

  The present invention has been invented in view of the above-described background art, and its problem is to dimm the discharge lamp in a discharge lamp lighting device capable of dimming the discharge lamp to a light output of less than 25% of the rating. Accordingly, it is an object of the present invention to provide a discharge lamp lighting device in which the lamp current is remarkably reduced due to the temperature characteristics of the discharge lamp itself or the lighting device, and troubles such as flickering and extinction do not occur.

  In order to solve the above problems, the present invention relates to a lighting unit capable of dimming and lighting the discharge lamp to less than 25% of the rated output, and changing the output of the lighting unit in accordance with the dimming signal. Dimming control means, discharge lamp detection means for detecting electrical parameters of the discharge lamp lighting state, and lighting control means for controlling the lighting means according to the lighting state detected by the discharge lamp detection means, In the discharge lamp lighting device provided, the discharge lamp detecting means detects an electrical parameter for detecting a lighting state when the discharge lamp lighting device is dimmed, and the control means detects the discharge lamp. The lighting means is controlled based on the electrical parameter detected by the detecting means.

  Moreover, it is preferable that the lighting control unit has a control unit that calculates the electrical parameter, and the control unit synthesizes the electrical parameter into one voltage.

  Furthermore, depending on the type of the discharge lamp, the voltage across the discharge lamp may abnormally increase due to a change in ambient temperature or the like, that is, the impedance of the discharge lamp may become abnormally large. In such a discharge lamp, it is preferable that the discharge lamp detection means detects at least an impedance parameter that is functionally related to the impedance of the discharge lamp.

  Furthermore, it is more preferable that the electrical path for detecting the impedance parameter and the electrical path for detecting the abnormal parameter are the same because the number of electronic components constituting the discharge lamp lighting device can be reduced.

  In addition, it is more preferable to provide an impedance element in parallel with the discharge lamp and detect a combined impedance of the impedance of the discharge lamp and the impedance element because a change in the impedance of the discharge lamp can be directly detected.

  In this specification, the term “discharge lamp” refers to a fluorescent lamp for general illumination, a germicidal lamp, a fluorescent lamp for color illumination, a bulb-type fluorescent lamp, a hot cathode fluorescent lamp, a cold cathode fluorescent lamp. It is assumed that all light emitting means that emit light due to a discharge phenomenon are included. The shape may also be a straight pipe type mainly used for facilities and stores, a ring type mainly used for houses, or a compact type mainly used for downlight fixtures.

  Further, in this specification, the term “lighting means” means an inverter or the like that converts a DC voltage from a DC power source into a different high-frequency voltage (a voltage having a constant period of about 20 kHz to about 200 kHz). To do. For example, the “lighting means” may be an arbitrary inverter such as a half-bridge type inverter, a full-bridge type, a single stone type, a parallel type, or a push-pull type.

  Further, in this specification, the term “electrical parameter” refers to an electrical parameter such as a voltage applied to both ends of the discharge lamp, a current flowing through the discharge lamp, an impedance of the discharge lamp, or a power consumption of the discharge lamp, as well as a discharge parameter. It includes the luminous efficiency of the electric lamp (lumen per watt), the illuminance of the discharge lamp, the color temperature, the luminance, the luminous flux, the luminous intensity, the input current to the discharge lamp lighting device, the input power, and the like. In addition, electrical parameters such as the current flowing through each electrical component that constitutes the discharge lamp lighting device, the voltage applied to both ends of each electrical component, and the coldest spot temperature, tube wall temperature, or base temperature of the discharge lamp Various characteristics that indirectly reflect the above are also included. In short, any characteristic that is functionally related to an electrical parameter is included.

  Furthermore, in this specification, the term “controlling the output of the lighting means” means changing the operating frequency of the lighting means to substantially turn off the discharge lamp or increase or decrease the power supplied to the discharge lamp. In other words, it includes control of dimming or intermittently oscillating the discharge lamp.

  Further, in this specification, when referring to a connection mode of an electrical component such as an inductor or a capacitor, the term “connection” refers to a conductive path that may include additional components between two or more electrical components. It shall exist. For example, when one end of the inductance is connected to one end of the capacitor, even if another electrical component not directly related to the effect of the present invention is connected between the inductance and the capacitor, one end of the inductance is connected to the capacitor. It is assumed that it is connected to one end.

  Furthermore, in this specification, the term “electrical abnormal state of the discharge lamp” means a half-wave discharge state (emiless state) caused by the filament being consumed at the end of the life of the discharge lamp, one or both of the filaments. Including abnormal discharge conditions caused by deformation, abnormal discharge conditions caused by leakage of rare gas sealed in the discharge lamp, abnormal discharge conditions caused by poor contact between the discharge lamp and the discharge lamp lighting device, etc. This means that the electric characteristics such as the current flowing through the discharge lamp have different values from the normal lighting state.

  The deviation of the electric characteristic value in the electrical abnormal state of the discharge lamp is not only the voltage applied to both ends of the discharge lamp, the current flowing through the discharge lamp, or the power consumption of the discharge lamp, but also the high-pressure discharge lamp. Luminous efficiency (lumen per watt), discharge lamp illuminance, color temperature, brightness, luminous flux, luminous intensity, input current to the discharge lamp lighting device, input power, etc. are also included, the coldest spot temperature of the discharge lamp, Reflected in tube wall temperature or base temperature. In addition, it is indirectly reflected in the current flowing through each electrical component constituting the discharge lamp lighting device, the voltage applied to both ends of each electrical component, and the like. In short, any characteristic is included as long as the characteristic is different from the normal lighting state of the discharge lamp.

  Furthermore, in this specification, the term “functionally related” means a correspondence relationship in which when one electrical parameter is determined, another electrical parameter is determined in a corresponding manner, It does not necessarily mean that one electrical parameter determines only one other electrical parameter. For example, the illuminance of the discharge lamp, which is one electrical parameter, decreases when the ambient temperature of the discharge lamp decreases, and also decreases when dirt such as dust adheres to the discharge lamp. In this case, even if the illuminance due to the decrease in the ambient temperature and the illuminance due to dirt adhesion are substantially the same, the impedance of the discharge lamp, which is another electrical parameter, may be different. In this specification, even in such a case, it is assumed that the illuminance and the impedance of the discharge lamp are functionally related.

  Further, in this specification, the term “DC power supply” may be unidirectional, and may be, for example, a pulsating power supply after a commercial AC power supply is smoothed by a smoothing capacitor, or a smoothing capacitor. A chopper circuit may be further provided in the subsequent stage. Of course, it may be one that does not pulsate like a battery. In short, all power sources that are not negative with respect to changes over time are included.

  According to the discharge lamp lighting device of the present invention, a feedback circuit that keeps the power consumption of the discharge lamp substantially constant, and a feedback circuit that corrects the output by detecting an abnormal increase in lamp voltage or abnormal decrease in lamp current, etc. Because it is equipped with a lamp output according to the dimming signal when fully lit, and if normal dimming lighting cannot be transiently performed due to temperature changes, etc., the lamp output is controlled to increase, so the temperature is low. It is possible to prevent flickering and extinction that may occur when the discharge lamp is dimmed in an environment.

Example 1
Hereinafter, a discharge lamp lighting device 1 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a circuit diagram of the present embodiment, and FIG. 2 shows a block diagram of the control unit. 3 shows a plan view of the lighting device, and FIG. 4 shows a plan view of the lighting system. Furthermore, FIG. 5 shows the relationship between the light control signal and the illuminance. First, based on FIG.1 and FIG.5, the structure of the discharge lamp lighting device 1 is demonstrated.

  The discharge lamp lighting device 1 according to the present embodiment includes an AC-DC converter 20 including a diode bridge 11 connected to a commercial power source 21, c, and an electrolytic capacitor 13, a half-bridge inverter 14, and a control unit 15. And an LC resonance circuit 16, a dimming signal circuit 17, a fixed resistor 18, and a discharge lamp 19 (hereinafter referred to as a discharge lamp 19). The lighting means 2 in this case is an AC-DC converter 20, a half-bridge inverter 14, and an LC resonance circuit 16, and the lighting control means 3 is an A / C circuit of a control unit 15 to be described later, and a discharge lamp detection means 4. Is a B circuit of the fixed resistor 18 and the control unit 15 described later.

  The commercial power source 21 is a commercial AC power source, and the voltage is, for example, 100V, 200V, or 240V.

  The AC-DC converter 20 includes a diode bridge 11 that full-wave rectifies the power supply voltage of the commercial power supply 21, a boost chopper circuit 12 that boosts the output of the diode bridge 11, and an electrolytic capacitor 13 that stores the output voltage. . That is, the voltage of the commercial power source 21 is converted into a predetermined DC voltage.

  Here, when the voltage of the commercial power supply 21 is 100 V, for example, a voltage doubler rectifier circuit may be used instead of the diode bridge. When the voltage doubler rectifier circuit is used, the voltage of the commercial power supply 21 can be regarded as substantially equal to 200 V, and the current flowing through the circuit connected after the voltage doubler rectifier circuit is about half that of the case using the diode bridge. Therefore, the efficiency of the discharge lamp lighting device 1 can be increased. The step-up chopper circuit 12 functions to step up the peak value voltage 140V from the diode bridge 11 to a DC voltage of about 400V, for example. A circuit, a step-up / down chopper circuit, or a circuit in which a step-up chopper circuit and a step-down chopper circuit are connected in series may be used. In short, any circuit configuration may be used as long as it converts one DC voltage into another DC voltage.

  The half bridge inverter 14 has a series circuit of switching elements Q1 and Q2 connected between the output terminals of the AC-DC converter 20, and a control unit 15 for inputting the switching elements Q1 and Q2 is connected. The half-bridge inverter 14 is connected at its midpoint to the LC resonance circuit 16 connected thereto, and the fixed resistor that converts the current flowing through the half-bridge inverter 14 into a voltage on the lower side of the switching element Q2 and inputs the voltage to the controller. A device 18 is connected.

  In other words, the DC voltage obtained by the AC-DC converter 20 is smoothed by the electrolytic capacitor 13 and converted into a high-frequency rectangular wave voltage by the high-frequency switching operation of the half-bridge inverter 14 connected to both ends thereof, and the half-bridge is turned to the midpoint of the half-bridge. Is output. When this rectangular wave voltage is input to the LC resonance circuit 16, a substantially sinusoidal voltage is generated due to the resonance action and applied to both ends of the discharge lamp 19, and the discharge lamp 19 is lit. At this time, the voltage obtained by converting the current flowing through the switching element Q2 by the fixed resistor 18 and the voltage across the discharge lamp 19 are fed back to the control unit 15.

  It is a rectangular-wave-shaped dimming signal from the outside that determines the power for lighting the discharge lamp 19. In other words, the dimming signal circuit 17 generates a DC voltage whose magnitude is changed according to the ON width of the dimming signal from the outside, and this DC voltage is input to the C circuit of the control unit 15. In the present embodiment, a pulse signal of approximately 1 KHz from the infrared remote control light receiving unit is input to the dimming signal circuit 17 as a dimming signal, and the C circuit of the control unit 15 is supplied according to the on-duty of the pulse signal. The value of the input DC voltage is changed. The on-duty is 90 to 10%, the value of the DC voltage generated according to the on-duty is about 2.4V when fully lit, and about 0.6V when the dimming ratio is about 25% when the dimming lower limit is reached.

  Further, in the present embodiment, as the discharge lamp 19, a stem including an electrode is sealed at one end, and a stem without an electrode is sealed at a pair of ends, and an annular bending process or a bridge process is performed. The double ring fluorescent lamp is used. The double-ring fluorescent lamp is arranged concentrically and in the same plane with arc tubes having different ring diameters. Such a double ring fluorescent lamp has a rated lamp power of about 40 W, an outer diameter of the fluorescent lamp glass tube of about 192 mm, an inner diameter of about 106 mm, a rated lamp power of about 85 W, and an outer diameter of the fluorescent lamp glass tube. There are FHD85 with an approximate diameter of 342 mm, an inner diameter of about 256 mm, a rated lamp power of about 100 W, an FHD100 with an outer diameter of the glass tube of the fluorescent lamp of about 400 mm and an inner diameter of about 314 mm. These double ring fluorescent lamps are fluorescent lamps. The diameter of the glass tube is approximately 20 mm, which is thinner than that of the conventional glass tube having a diameter of approximately 29 mm.

  In such a double-ring fluorescent lamp, the diameter of the glass tube is small and the lamp current is difficult to flow. Therefore, in a normal lighting state, the lamp voltage tends to increase and the lamp impedance tends to increase. In particular, due to a decrease in ambient temperature, the lamp voltage may become very large and the lamp impedance may also increase.

  In addition, the discharge lamp 19 may be a thin tube fluorescent lamp having a glass tube diameter of 15 mm to 18 mm. Such a thin tube fluorescent lamp has a single annular shape, and includes an FHC 32 having an outer diameter of approximately 299 mm and an inner diameter of approximately 267 mm, an FHC 40 having an outer diameter of approximately 373 mm, and an inner diameter of approximately 341 mm. In such a thin tube fluorescent lamp, the lamp voltage may become very large due to a decrease in the ambient temperature, as in the FHD series.

  In addition, for example, a straight tube shape of a so-called 4-foot facility / store with a tube length of about 1198 mm, where the glass tube has a thin diameter, the diameter of the glass tube is about 15.9 mm, the lamp power is about 54 W, the lamp current There are HO lamps with about 400 mA and lamp voltage of about 135 V, HE lamps with the same glass tube diameter, lamp power of about 28 W, lamp current of about 170 mA, and lamp voltage of about 165 V. Although these lamps have the same tube length of 4 feet, the lamp power is about 40 W, the lamp current is about 380 mA, the lamp voltage is a straight tube rapid type lamp having a glass tube diameter of about 32.5 mm larger than that of the HO lamp or HE lamp. Compared with FLR40 of about 105V, lamp power of about 36W, lamp current of about 400mA, and FLR40S / 36 of lamp voltage of about 90V, the rated lamp voltage is l: 1.4 times or more even with the same shape and size. Have a difference. That is, the lamp impedance during normal lighting is larger than that of the straight tube rapid lamp. Moreover, the impedance difference of the lamp is further significantly increased due to the decrease in the ambient temperature. The discharge lamp 19 of the present embodiment may be a straight tube lamp in which the impedance of the lamp increases remarkably due to such a decrease in ambient temperature.

  Next, as shown in FIGS. 1 and 2, the control unit 15 includes an A circuit, a B circuit, and a C circuit.

  The A circuit includes a resistor A1, a capacitor A2, an operational amplifier A3, and a driver A4. This A circuit receives a voltage feedback of a signal obtained by converting the current flowing through the switching element Q2 by the fixed resistor 18 and reflects it in the drive signal of the inverter.

  The B circuit includes resistors B1, B2, and B3 and an operational amplifier B4. The B circuit outputs a DC voltage proportional to the lamp voltage of the discharge lamp 19 by dividing the voltage by the voltage resistors B1 and B2 at both ends of the discharge lamp 19 and inputting the divided voltage to the operational amplifier B4 which is a buffer circuit.

  The C circuit includes an OR circuit composed of diodes C1 and C2. The C circuit compares the output voltage of the dimming signal circuit 17 with the output voltage of the B circuit unit, and inputs the larger voltage to the A circuit unit.

  FIG. 3 shows an example of the illuminating device 6. As the discharge lamps 19A and 19B, straight tube HO lamps mainly used for facilities and stores are used. That is, the lighting device 6 includes the discharge lamp lighting device 1 described above, the main body 9 to which the discharge lamp lighting device 1 is mounted, and the discharge lamp lighting device 1 that is supplied with power, for example, the discharge lamps 19A and 19B. Has been. The main body 5 represents a so-called Fuji lighting device for two lights. S1 is a socket in which the discharge lamp 19A is mounted, and R is a white reflector disposed on the side facing the discharge lamps 19A and 19B.

  Since discharge lamps such as HO, HE, FLR40 and FLR40S / 36 have the same tube length of approximately 1198 mm and differ only in the base dimensions, these discharges can be performed by one type of lighting device 6 only by changing the socket S1. The lamp can be shared. Accordingly, the user can use the discharge lamp without worrying about the type of the discharge lamp, and can select the discharge lamp according to the user's preference such as the cost, design, and light output of the discharge lamp. .

  As shown in FIG. 4, an illumination system is configured by the plurality of illumination devices 6 described above and a control device S that controls these illumination devices 6. Each lighting device 6 includes a human body sensor (not shown), and the control device S controls, for example, the human body sensors and light fluxes of twelve lighting devices A to L collectively by a program. In the present embodiment, the above-described HO lamps are mounted as the discharge lamps on the lighting devices A to I, and the light output of the light beams from the lighting devices J to L on the window side where external light enters is lower than that of the HO lamp. However, the low-cost FLR40S / 36 is installed.

  As a feature of the control device S, the discharge lamp 19 is turned on when a person is sensed by the human body sensor, and is turned off when the person is absent, the input of the mounting state of the discharge lamp 19, and the lighting device 6 is turned on / off. It has a program control function capable of setting conditions, and can realize an extremely efficient and energy saving lighting system according to the installation environment.

  Next, the operation of the control unit 15 will be described.

  In the B circuit section, the lamp voltage b of the discharge lamp 19 is converted into a DC voltage by an operational amplifier B4 which is a buffer circuit, and is output as a lamp voltage b '. The lamp voltage b 'and the output voltage c of the dimming signal circuit 17 are input to the C circuit unit, and the output voltage c' is input to the A circuit as a reference voltage for feedback control. In the A circuit, the drive signal a 'is controlled so that the voltage a fed back from the source current of the half-bridge inverter 14 by the fixed resistor 18 is equal to the reference voltage (output voltage c').

  That is, in a normal lighting state, a relationship of dimming signal voltage c> lamp voltage b 'is established between the dimming signal voltage c and the lamp voltage b'. The output voltage c ′ of the OR circuit and the reference voltage (output voltage c ′) for feedback control are equal to the dimming signal voltage c, and the discharge lamp 19 is output power corresponding to the dimming signal input to the dimming signal circuit 17. Light.

  On the other hand, in a state where the lamp voltage becomes abnormally high due to a change in ambient temperature or the like, the relationship between the dimming signal voltage c and the lamp voltage b ′ is reversed by the above-described relationship, and the dimming signal voltage c <lamp voltage b. Thus, the output voltage c ′, which is the output of the OR circuit, that is, the reference voltage for feedback control is equal to the lamp voltage b ′, and the discharge lamp 19 is turned on with a larger output power than when the dimming signal is used. .

  In the control unit, the lamp voltage b ′ serves to limit the lower limit of the dimming control. Normally, the dimming signal voltage c is higher than this voltage, so there is no effect, but the ambient temperature decreases. When the voltage across the fluorescent lamp rises abnormally due to the above, the lamp voltage b ′ becomes higher than the dimming signal voltage c, and the output lower limit value of dimming control increases. At this time, when the dimming signal is changed, the output of the discharge lamp does not decrease from the dimming signal where the lamp voltage b '= the dimming signal voltage c.

  By this operation, it is possible to prevent flickering or extinction that may occur when the discharge lamp is dimmed in a low temperature environment.

  The graph of FIG. 5 shows the relationship between the external dimming signal (dimming signal voltage c) -illuminance when the circuit of the present embodiment is used. The dimming signal is fully lit when the duty is 0%, 10% dimming when the duty is 90%, and the dimming signal is converted by the dimming signal circuit 17 so as to change linearly during that period and is input to the control unit 15. In a 25 ° C environment, the light is linearly adjusted to 10%, but at 0 ° C, the light control signal duty is increased by about 70% and the light control ratio is about 30%. But the illuminance has not decreased. That is, in the 0 ° C. environment, when the duty of the dimming signal from the outside is about 70%, the lamp voltage b ′ = the dimming signal voltage c as described above in the control unit, so that the discharge lamp Holds the output.

  As described above, according to the present embodiment, the feedback circuit that keeps the power consumption of the discharge lamp 19 substantially constant, and the feedback circuit that corrects the output by detecting an abnormal increase in lamp voltage or abnormal decrease in lamp current, etc. Because it is equipped with a lamp output according to the dimming signal when fully lit, and if normal dimming lighting cannot be transiently performed due to temperature changes, etc., the lamp output is controlled to increase, so the temperature is low. It is possible to prevent flickering and extinction that may occur when the discharge lamp is dimmed in an environment.

  Note that the lighting control unit 3 may control the lighting unit 2 in response to a control signal from either the fixed resistor 18 or the B circuit of the control unit 15.

  Further, the lighting control means 3 may control the output of the lighting means at the time of normal lighting by receiving a control signal from both or one of the fixed resistor 18 and the B circuit of the control unit 15, or dimming The lighting control means 3 may control the output of the lighting means in response to a control signal from both or one of the fixed resistor 18 and the B circuit of the control unit 15 at the time of lighting.

  Furthermore, feedback of an electrical parameter that works transiently to prevent flickering and extinction may be combined with a control signal that controls the degree of dimming.

  Furthermore, although not shown, the lighting control means controls the driving frequency of the half-bridge inverter 14 and changes the power supplied to the discharge lamp 19 by utilizing the resonance action of the inductor L and the capacitor C4. It goes without saying that preheating, lighting, etc. of the discharge lamp 19 are also controlled.

(Example 2)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 6 shows a circuit diagram of the present embodiment, and FIG. 7 shows a circuit diagram of the control unit 15 and its peripheral circuits. FIG. 8 shows a characteristic curve showing the relationship between the equivalent impedance of the discharge lamp and the voltage (cathode voltage of the diode D1) reflecting the equivalent impedance of the discharge lamp detected by the discharge lamp detecting means. FIG. FIG. 5 is a characteristic diagram showing how much the equivalent impedance value of the lamp becomes flickering in the discharge lamp. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, in the first embodiment, a resistor R1 that is a first impedance element is connected between the positive side of the electrolytic capacitor 13 and the output end of the LC resonance circuit 16, and the discharge lamp 19 In parallel, three resistors, a resistor R2, a resistor R3 as a second impedance element, and a resistor R4 are connected in series. Further, the FHD 100 described in the first embodiment is used as the discharge lamp 19, and the equivalent impedance of the FHD 100 is Rla.

  Further, the control unit 15 controls the switching element (not shown) included in the step-up chopper circuit 12, the switching element included in the half-bridge inverter 14, and further the voltage of the discharge lamp 19 by the voltage fed back from the fixed resistor 18. An integrated circuit MCZ series manufactured by Shindengen Electric Industry Co., Ltd., which has a function of controlling output power, is used.

  Further, the high voltage side of the resistor R3 is designated as point B, the high voltage side of the resistor R4 is designated as point C, and the voltages to the circuit ground at the points B and C are designated as VB and VC, respectively. To the control unit 15. Furthermore, the control unit 15 has therein a first threshold value Vth1 having a threshold voltage of 1.5V and a second threshold value Vth2 having a threshold voltage of 4.0V that is larger than the first threshold value Vth1. ing. When the cathode voltage of the diode D1 exceeds the first threshold value Vth1, the lower limit of the dimming control is limited by the control unit 15, that is, the output of the discharge lamp 19 is controlled not to decrease. Further, when the cathode voltage of the diode D1 exceeds the second threshold value Vth2, the control unit 15 stops the oscillation of the half bridge inverter 14, and the discharge lamp 19 is turned off. That is, the control unit 15 corresponds to the discharge lamp detection unit 4 in the first embodiment and also corresponds to the lighting control unit 3 in the first embodiment.

  The voltage VB is an impedance parameter that is functionally related to at least the impedance Rla of the discharge lamp 19 so that the impedance Rla increases as the voltage VB, which is an electrical parameter, increases. The diode D1 and the control unit 15 detect impedance parameters that indirectly reflect the impedance parameters R1 to R4 that are impedance elements.

  The voltage VC, which is an electrical parameter similar to the voltage VB, is functionally related to the increase in the voltage across the discharge lamp 19 when the discharge lamp 19 is in an electrically abnormal state such as an Emileless state. When the voltage VC, which is the abnormal parameter, exceeds 4.0 V, which is the second threshold value Vth2, as described above, the control unit 15 stops the oscillation of the half-bridge inverter 14, and the discharge lamp 19 is turned off.

  Here, the impedance parameter gradually increases as the ambient temperature of the discharge lamp 19 gradually decreases over a relatively long time such as several minutes or tens of minutes. Thus, the abnormal parameter increases instantaneously in several milliseconds such as the Emires state or the attachment / detachment of the discharge lamp 19. An increase in the abnormal parameter may cause deterioration of the discharge lamp lighting device.

  If the impedance parameter gradually increases like the impedance parameter, the output decrease of the discharge lamp 19 is limited when the impedance parameter exceeds the first threshold value Vth1, and the second threshold value Vth2 is hardly reached. However, if it increases instantaneously like an abnormal parameter, the first threshold value Vth1 is instantaneously reached to the second threshold value Vth2, so that in such an abnormal state, the half-bridge inverter 14 The oscillation is stopped.

  In the present embodiment, the detection of the impedance parameter and the detection of the abnormal parameter are performed from the resistor R1 to the resistor R4 by using the same electrical path of the diode D1 and the control unit 15. As a result, the number of circuit components can be reduced.

  Next, the operation of the present embodiment will be described.

Assuming that the high voltage side of the resistor R1 is point A, the voltage to the circuit ground at point A is VA, and the forward voltage of the diode D1 is VF, the voltages VB and VC can be expressed as follows.

VB = VA × ((R3 + R4) × Rla) / (R1 × (R2 + R3 + R4 + Rla) + Rla × (R2 + R3 + R4)) 1)

VC = VB × R4 / (R3 + R4) −VF (2)

Here, in the present embodiment, the voltages VA≈300V, R1≈800 kΩ, R2≈2000 kΩ, and R3 = R4≈100 kΩ are set. In the state where the discharge lamp 19 is normally lit, the impedance Rla is about several hundred Ω, that is,

Resistors R1, R2, R3, R4 >> Impedance Rla (3)

The relationship holds. Therefore, the equation (1) is as follows.

VB = VA × (R3 + R4) / (R1 × (R2 + R3 + R4)) × Rla (4)

Further, when the discharge lamp 19 enters an abnormal state such as an Emires state, that is, when the impedance Rla = ∞, the expression (1) is as follows.

VB = VA × (R3 + R4) / (R2 + R3 + R4) (5)

In the state where the discharge lamp 19 is normally lit, in equation (4), since (R1 × (R2 + R3 + R4)) >> (R3 + R4), VB≈0V, and the DC voltage from the dimming signal circuit 17 is 0. .6V (dimming ratio is approximately 25%) to 2.4V (dimming ratio is approximately 100%) is dominant. Therefore, the discharge lamp 19 is dimmed and controlled by feedback from the fixed resistor 18.

  Here, FIG. 8 shows a change in the cathode voltage of the diode D1 when the impedance Rla of the discharge lamp 19 increases. When impedance Rla = ∞, VB takes a certain value of voltage, as can be seen from equation (5).

  Further, FIG. 9 shows how much the impedance Rla of the discharge lamp 19 is lowered or increased and the discharge lamp 19 blinks (not pointed) or flickers. As can be seen from FIG. 9, when the impedance Rla is larger than about 20 kΩ, the discharge lamp 19 starts to flash (dot) or flicker.

  That is, in the circuit diagram of FIG. 6, when impedance Rla≈20 kΩ, impedance parameter (cathode voltage of diode D1)> first threshold Vth1 and second threshold Vth2> impedance parameter (cathode voltage of diode D1) When a constant such as the resistor R1 is set so that the discharge lamp 19 is dimmed by feedback from the fixed resistor 18, the discharge lamp 19 can be affected even when there is an influence of a change in ambient temperature or the like. Thus, since the impedance parameter does not reach the s2th threshold value Vth2, the oscillation of the half-bridge inverter 14 is not stopped.

  In the present embodiment, when the voltage VB is calculated based on the equation (4) using the above-described resistance value, the voltage VB (impedance parameter) ≈1.7V, and the voltage VB≈1.7V> the first threshold value Vth1. = 1.5V, and the second threshold value Vth1 = 4.0V> voltage VB≈1.7V. Therefore, it is possible to prevent flickering or extinction that may occur when the discharge lamp 19 is dimmed in a low temperature environment.

  As described above, according to the present embodiment, the feedback circuit that keeps the power consumption of the discharge lamp 19 substantially constant, and the feedback circuit that corrects the output by detecting an abnormal increase in lamp voltage or abnormal decrease in lamp current, etc. Because it is equipped with a lamp output according to the dimming signal when fully lit, and if normal dimming lighting cannot be transiently performed due to temperature changes, etc., the lamp output is controlled to increase, so the temperature is low. It is possible to prevent flickering and extinction that may occur when the discharge lamp is dimmed in an environment. Further, when the discharge lamp 19 is in an electrically abnormal state such as an Emileless state, the control unit 15 can stop the oscillation of the half-bridge inverter 14 and turn off the discharge lamp 19. Thereby, the electrical stress concerning the circuit components which comprise the discharge lamp lighting device 1 can be reduced.

  Note that operations and effects that are not particularly mentioned in the present embodiment are the same as those in the first embodiment.

1 is a circuit diagram showing a discharge lamp lighting device according to a first embodiment of the present invention. It is a block diagram of a control part same as the above. It is a top view which shows an illuminating device. It is a top view which shows an illumination system. It is a graph which shows the relationship between a light control signal and illumination intensity It is a circuit diagram which shows the discharge lamp lighting device which concerns on the 2nd Embodiment of this invention. It is a circuit diagram which shows a control part and its peripheral circuit. It is a characteristic view which shows the relationship between the equivalent impedance of a discharge lamp and the voltage (cathode voltage of the diode D1) reflecting the equivalent impedance of the discharge lamp which a discharge lamp detection means detects. It is a characteristic view showing how the equivalent impedance value of the discharge lamp becomes to cause flickering in the discharge lamp. It is a circuit diagram which shows the conventional discharge lamp lighting device. It is a characteristic view showing the lamp voltage-lamp current characteristic of a discharge lamp same as the above. It is a circuit diagram which shows a discharge lamp lighting device described in Unexamined-Japanese-Patent No. 2003-77696.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp lighting device 2 Lighting means 3 Lighting control means 4 Discharge lamp detection means 15 Control part 19 Discharge lamp (discharge lamp)
Vth1 first threshold value Vth2 second threshold value 14 inverter 16 LC resonance circuit R1 first impedance element (impedance element)
R3 Second impedance element 5 Main body 6 Lighting device S Control device

Claims (11)

A lighting means capable of dimming and lighting the discharge lamp to less than 25% of the rated output, a discharge lamp detecting means for detecting an electrical parameter of the lighting state of the discharge lamp, and an electrical parameter and dimming detected by the discharge lamp detecting means And a lighting control means for controlling the output of the lighting means in accordance with the signal. The discharge lamp detecting means is an electrical parameter for detecting a lighting state when the discharge lamp lighting apparatus is dimmed. Is detected from two or more places, and the lighting control means controls the lighting means based on the electrical parameters and dimming signals detected from the two or more places. 2. The discharge lamp lighting device according to claim 1, wherein the lighting control means includes a control unit that calculates an electrical parameter, and the control unit combines the electrical parameter into one voltage. 2. The discharge lamp lighting device according to claim 1, wherein the electrical parameter is an impedance parameter that is functionally related to at least the impedance of the discharge lamp, and the discharge lamp detecting means detects the impedance parameter. The discharge lamp detection means has a first threshold value and a second threshold value greater than the first threshold value, and is connected to the discharge lamp via an impedance element, and the impedance parameter detected by the discharge lamp detection means. 4. The discharge lamp lighting device according to claim 3, wherein the lighting means is controlled by the lighting control means when at least a first threshold value is exceeded. The electrical parameter is an abnormal parameter that is functionally related to at least the electrical abnormal state of the discharge lamp, and only when the increase value of the abnormal parameter detected by the discharge lamp detection means exceeds the second threshold value. 5. The discharge lamp lighting device according to claim 4, wherein the lighting means is controlled by the lighting control means. 6. The discharge lamp lighting device according to claim 5, wherein the electrical path for detecting the impedance parameter and the electrical path for detecting the abnormal parameter are the same. The lighting means has an inverter and an LC resonance circuit connected to the output end of the inverter, the input end of the lighting means is connected to a DC power source, and the output end of the LC resonance circuit is connected to a discharge lamp, A second impedance element connected in parallel to the discharge lamp from the positive potential side of the DC power supply via the first impedance element is provided, and an impedance parameter reflected in the second impedance element is detected. The discharge lamp lighting device according to claim 3. A discharge lamp lighting device according to any one of claims 1 to 7, a main body on which the discharge lamp lighting device is mounted, and a discharge lamp to which electric power is supplied from the discharge lamp lighting device. Lighting device. The discharge lamp has a double ring structure in which a stem including an electrode is sealed at one end and a stem without an electrode is sealed at each end of the pair, and is processed into an annular shape. The lighting device according to claim 9, wherein the lighting device is 20 mm. The lighting device according to claim 9, wherein the diameter of the glass tube of the discharge lamp is 15 mm to 18 mm. A lighting system comprising a plurality of lighting devices according to any one of claims 8 to 10 and a control device that controls the lighting devices.

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