JP4000618B2 - Discharge lamp lighting device and lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a discharge lamp lighting device and an illumination device using the same.
[0002]
[Prior art]
  When the discharge lamp reaches the end of its life, it causes an abnormal discharge that becomes a half-wave discharge. Due to this abnormal discharge, the vicinity of the electrode is abnormally heated. In particular, in a discharge lamp with a thin glass bulb, the distance between the electrode and the glass bulb is small, and therefore the temperature of the glass bulb becomes very high due to abnormal discharge. For this reason, there is a problem that glass bulbs, plastic caps, sockets and the like are melted.
[0003]
    FIG. 13 is a circuit diagram showing a discharge lamp lighting device of prior art 1.
[0004]
  In the figure, 131 is an AC power source, 132 is a rectifier circuit, 133 is a DC-DC converter, 134 is a high frequency generating means, 135 is a load circuit, and 136 is an end of life detecting means.
[0005]
  The load circuit 135 includes an inductor 135a as a current limiting element, a series circuit of a discharge lamp 135b, and a capacitor 135c connected in parallel with the discharge lamp 135b.
[0006]
  The end-of-life detection means 136 is connected between both ends of the discharge lamp 135b, and is configured to control the high-frequency generation means 134 with its output.
[0007]
  Then, when the DC voltage rectified by the rectifier circuit 132 and smoothed and voltage-adjusted by the DC-DC converter 133 is applied to the input end of the high frequency generator 134, the high frequency generator 134 is connected to the output end of the DC voltage. Generates a high frequency voltage. The high frequency voltage is applied to the load circuit 135. The high frequency voltage applied to the load circuit 135 is applied to the discharge lamp 135b and the capacitor 135c via the inductor 135a. Since the inductor 135a and the capacitor 135c resonate moderately, a high voltage required for starting is applied to the discharge lamp 135b, and the discharge lamp 135b starts and lights up.
[0008]
  During the lighting of the discharge lamp 135b, the end of life detection means 136 continues to monitor the voltage between the electrodes of the discharge lamp 135b. When the discharge lamp 135b reaches the end of its life, the end of life detection means 136 detects it. The detection signal is input to the control terminal of the high frequency generation means 134 and stops the operation of the high frequency generation means 134.
[0009]
    FIG. 14 is a graph showing the load characteristics of the load circuit in the prior art 1.
[0010]
  In the figure, the horizontal axis represents the output current, and the vertical axis represents the output voltage.
[0011]
  Curve A is a load characteristic curve when all lights are lit, curve B is a load characteristic curve when dimming is lit, curve c is an operating characteristic curve of a normal discharge lamp, and curve d is an operating characteristic curve at the end of life.
[0012]
  The load characteristic is an arc-like resemblance for both all-light lighting and dimming lighting. In the discharge lamp, the lamp voltage gradually increases as the life of the discharge lamp increases, so that the operating characteristics shift upward in the figure.
[0013]
  Therefore, when the discharge lamp is normally lit when operating normally, it operates at the intersection X1 between the curve A and the curve c in the figure. When the dimming is on, it operates at the intersection X2 between the curve B and the curve c. That is, at the time of dimming lighting, both the output current and the output voltage are reduced to approximately the same extent.
[0014]
  On the other hand, when the discharge lamp reaches the end of its life when all the lights are on, the discharge lamp operates at the intersection Y between the load characteristic curve A and the operating characteristic curve d. Absent. For this reason, the above-mentioned melting problem occurs.
[0015]
  On the other hand, Japanese Patent Application Laid-Open No. 1-231295 discloses a high-frequency generating means to the extent that other normal discharge lamps can be kept lit if a discharge lamp abnormality is detected when a plurality of discharge lamps are lit in parallel. It is disclosed that the output is reduced (prior art 2). According to this prior art 2, since the remaining discharge lamp is lit with the output of the high-frequency generating means being reduced at the end of the life, a minimum illumination level can be secured.
[0016]
[Problems to be solved by the invention]
  Prior art 1 has a safety problem because the discharge lamp is darkened by the operation stop of the high-frequency generating means.
[0017]
  In the prior art 2, when this is applied to a discharge lamp having a thin tube, the temperature of the glass bulb becomes too high even if the output of the high frequency generating means is reduced. Further, although it is disclosed that the output is reduced until the abnormal discharge lamp cannot maintain the discharge, it is difficult to maintain the normal discharge lamp in this state. In particular, in household lighting fixtures, two or more discharge lamps having different rated power consumption are often lit by a single high-frequency generating means, so that it is extremely difficult to keep the remaining normal discharge lamps lit in an abnormal state. It is.
[0018]
  SUMMARY OF THE INVENTION An object of the present invention is to provide a discharge lamp lighting device that turns off a discharge lamp at the end of its life and a lighting device using the same, even if it is a thin tube discharge lamp without using a complicated protection circuit.
[0019]
[Means for achieving the object]
    The discharge lamp lighting device of the invention of claim 1 is a discharge lamp,Connected in series with the discharge lampInductance andConnected in parallel with the discharge lampIncluding capacitanceThe first load characteristic having an open-circuit voltage lower than the lamp voltage at the end of the life of the discharge lamp and a relatively large short-circuit current during all-light lighting or all-light and electrode preheating, and dimming lighting Exhibiting a large open-circuit voltage compared to the open-circuit voltage in the first load characteristic during time or dimming and starting, and a second load characteristic with a small short-circuit current compared to the short-circuit current in the first load characteristic; and In addition, the discharge lamp at the normal time can form the operating point with respect to the first and second load characteristics, but the discharge lamp at the end of the life is configured not to form the operating point.A load circuit; high-frequency generating means for supplying a high-frequency output to the load circuit; control means for setting all-light lighting and dimming lighting;Capacity changing means for changing the capacity of the capacitance connected in parallel with the discharge lamp;It is characterized by comprising.
[0020]
  In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.
[0021]
  First, the discharge lamp will be described.
[0022]
  The discharge lamp is not particularly limited, but may be a thin tube discharge lamp. As used herein, the discharge lamp of a thin tube is, for example, a compact fluorescent lamp, a bulb-type fluorescent lamp, or a ring-shaped fluorescent lamp dedicated to high-frequency lighting (FHC20, FHC27, FHC34 types, all having a tube outer diameter of 16.5 mm. It has the expected effect on the production of the applicant. However, it is also effective for general fluorescent lamps.
[0023]
  Next, the load circuit will be described.
[0024]
  The load circuit is a discharge lamp,Connected in series with the discharge lampInductance andConnected in parallel with the discharge lampIf the capacitance is included, the specific circuit connection is not limited. In the present invention, the load circuit refers to a circuit including a discharge lamp and a current limiting element for stably lighting the discharge lamp as viewed from the high-frequency generating means. The circuit configuration used to start the discharge lamp may be added to the load circuit, but is not a requirement.
[0025]
  The load circuit isThe restAlthough the specific circuit configuration is not limited, in general, the inductance is mainly used as a current limiting element of the discharge lamp. In this case, it can be connected to the load circuit in the form of a leakage inductance of an inductor connected separately from the high frequency generation means or an output transformer constituting a part of the high frequency generation means.
[0026]
  Capacitance is generally used for preheating the discharge lamp, and other capacitance is connected in series with the current limiting element and can be used as part of the current limiting element or for DC cutting. Many.
[0027]
  One or a plurality of load circuits are allowed to be used. In the case of a plurality, they can be connected in parallel to the high-frequency generating means. In addition, a plurality of discharge lamps can be connected in series to one load circuit.
[0028]
  The load characteristics of the load circuit will be described.
[0029]
  The load characteristic of the load circuit is given as desired by appropriately setting, for example, constants of inductance and capacitance, which are part of the components of the load circuit, or the circuit configuration of the load circuit. In addition, the output frequency of the high-frequency generating means can be given as desired by appropriately setting the output frequency according to the operating state of the discharge lamp.
[0030]
  Here, the operating state of the discharge lamp means that all or part of a series of operating states of electrode preheating, starting, and lighting are included. Furthermore, lighting is a concept including both all-light lighting and dimming lighting.
[0031]
  Therefore, in the implementation of the present invention, the load characteristic changes to a predetermined value when changing between the operation modes of all-light lighting and dimming lighting in lighting. Also, the load characteristics can be changed when switching between the operation modes of electrode heating and starting, or switching between the operation modes of electrode heating, starting and all-light lighting. Furthermore, the load characteristics can be changed when switching all the operation modes of electrode heating, start-up, all-light lighting, and dimming lighting.
[0032]
  The load characteristics of the load circuit are configured as follows. That is, the load circuit exhibits a first load characteristic with a relatively low open-circuit voltage and a large short-circuit current during all-light lighting or during all-light and electrode heating, and the first load characteristic during dimming lighting or during dimming lighting and start-up. 1 shows a load characteristic with an open circuit voltage greater than the open circuit voltage of the first load characteristic and a short circuit current smaller than the short circuit current of the first load characteristic, and the discharge lamp in the normal state with respect to the first and second load characteristics However, the discharge lamp at the end of life is configured not to form an operating point.
[0033]
  The high frequency generating means will be described.
[0034]
  The high frequency generation means may have any configuration as long as it can supply a high frequency output to the load circuit.
[0035]
  The high frequency generation means can employ any known circuit system for high frequency generation. For example, inverters such as a blocking oscillation type, a multivibrator type, a half bridge type, a full bridge type, and variations thereof can be used.
[0036]
  Furthermore, either the voltage resonance type or the current resonance type may be used. In the case of the current resonance type, switching means having a relatively low withstand voltage can be used, and the frequency is set regardless of the inductance and capacitance of the load circuit. Therefore, it is particularly suitable for the implementation of the present invention.
[0037]
  Furthermore, in order to dimm the discharge lamp, the high-frequency generating means can use conventional means for reducing output such as changing the on-duty.
[0038]
  An appropriate power source can be used for the high-frequency generating means, but generally a DC power source obtained by rectifying and smoothing a commercial AC power source can be used. To perform smoothing, a smoothing capacitor can be used. However, since the power factor is deteriorated, this can be avoided, a desired power supply voltage can be obtained, and a DC-DC converter with less harmonic distortion can be used. it can.
[0039]
  The control means will be described.
[0040]
  The control means can set the lighting state of the discharge lamp to at least all-light lighting and dimming lighting. The control means can control the high frequency generating means or the DC-DC converter constituting the direct current power source to set the operation mode to either the all-light mode or the dimming mode. The dimming mode may be either step dimming or continuous dimming.
[0041]
  Further, it can be configured to be able to perform this by adding control mode switching such as turning off the light as necessary.
[0042]
  As a method for operating the control means, a method such as a remote control using a wall switch, infrared rays, or the like can be employed.
[0043]
  Next, capacity changing means will be described.
[0044]
  The capacity changing means is means for changing the capacity of the capacitance connected in parallel with the discharge lamp.
[0045]
  Finally, the operation will be described.
[0046]
  In the present invention, at the time of all-light lighting or electrode heatingSince the load circuit exhibits the first load characteristic,Although the open circuit voltage is low as described above, the short circuit current is relatively large. If the discharge lamp reaches the end of its life when all light is on, the lamp voltage willOf the first load characteristicThe discharge lamp is higher than the open circuit voltage.An operating point cannot be formed for the first load characteristic. As a result, the discharge lampIt is no longer possible to keep the light on and it goes out. When a plurality of load circuits are connected in parallel, the discharge lamp at the end of its life is extinguished as described above, but the normal discharge lamp continues to be lit. Also during electrode heatingAs wellLow open-circuit voltage and large short-circuit current enable the electrode to be heated sufficiently or in a short time, and no high voltage is applied between the electrodes during electrode heating, so it can be started forcibly when the electrode temperature is low It will not be done. This has the effect of reducing electrode damage.
[0047]
  On the other hand, at the time of dimming lighting or at the time of dimming and startingSince the load circuit exhibits the second load characteristic,Although the open circuit voltage is high, the short-circuit current is small, so that the dimming degree can be increased, that is, the light can be dimmed deeply. Also when startingAs wellHigh open circuit voltage, small short circuit currentThe second load characteristic is obtained.
[0048]
  The present invention relates to all-lighting and dimming lighting, or electrode heating and starting, and / or electrode heating, starting and all-lighting, or further, electrode heating, starting, all-light Load characteristics of the load circuit at the time of lighting and dimming lighting as described aboveFor first or second load characteristicsSince it changes, favorable lighting or starting can be performed smoothly.
[0049]
  Here, it will be as follows if the case where this invention is applied over all the operation modes is demonstrated. That is, when heating the electrode before starting, a relatively low open-circuit voltage and a large short-circuit currentFirstUse load characteristics. Thereby, sufficient electrode heating can be performed. Next, when startingThan that of the first load characteristicHigh open circuit voltage, small short circuit currentSecondUse load characteristics. Thereby, starting is accelerated | stimulated by application of a high open circuit voltage. Once started, the load characteristics may be changed to when all light is on. By doing in this way, electrode heating can be performed appropriately, without using a special electrode preheating circuit.
[0050]
  Even if the load characteristic of the load circuit is either the first load characteristic or the second load characteristic, when the discharge lamp reaches the end of its life, the lamp voltage increases and an operating point can be formed for the load characteristic. As a result, the discharge lamp is turned off.
[0051]
  The above control can be easily performed automatically by, for example, incorporating a program in an IC or the like. However, this can be done manually if necessary.
[0052]
  Moreover, when implementing said control, it can employ | adopt as needed to change also the output frequency of a high frequency generation means interlockingly. That is, the frequency is lowered during preheating. Increase frequency at start-up. Lower when all lights are on. The frequency at the time of preheating and that at the time of all-light lighting may be equal or different.
[0053]
  In addition to the above, the present invention can change the load characteristics of the load circuit, particularly the open circuit voltage, with a simple configuration. That is, the load characteristic is changed by changing the capacitance of the capacitance connected in parallel with the discharge lamp. When the capacitance is reduced, the natural resonance frequency of the load circuit is increased. Therefore, if the output frequency of the high-frequency generator is unchanged, the open circuit voltage applied to the discharge lamp is reduced.
[0054]
  On the other hand, when the capacitance is increased, the natural resonance frequency of the load circuit is lowered, so that the open circuit voltage applied to the discharge lamp is increased.
[0055]
  The short-circuit current can be effectively performed by changing the frequency of the high-frequency generating means, for example. That is, the frequency is lowered. This reduces the impedance of the load circuit and increases the short-circuit current. On the contrary, when the frequency is increased, the impedance of the load circuit is increased and the short-circuit current is decreased.
[0056]
  The capacity variable means for changing the capacity of the capacitance switches a capacitor prepared in advance by a switch, for example.
[0057]
  The change in capacitance can be made, for example, at the end of the life of the discharge lamp. It is possible to change the load characteristics at the end of the life so that the discharge lamp is turned off more reliably. That is, at the end of the life, the capacitance is changed to a small value to lower the open circuit voltage.
[0058]
  In addition, the capacitance can be changed between all-light lighting and dimming lighting. That is, during dimming, the capacitance is increased to increase the open circuit voltage.
[0059]
  Furthermore, desired electrode heating can be performed by increasing the electrode heating current by relatively increasing the capacitance of the discharge lamp when it is started.
[0060]
  Next, a first aspect of the discharge lamp lighting device of the present invention will be described.
[0061]
  The first aspect includes a plurality of load circuits each including a discharge lamp, an inductance, and a capacitance and connected in parallel; and a common high-frequency generation means for supplying a high-frequency output to each load circuit; The discharge circuit is turned off, but a normal discharge lamp is given load characteristics to the load circuit so that all light is continuously turned on.
[0062]
  In this aspect, if any one of the plurality of load circuits connected in parallel is a load characteristic that turns off when the discharge lamp reaches the end of its life and the remaining discharge lamps continue to be lit, the load characteristic applying means is Any configuration may be used. However, typically, it is a first load characteristic with a relatively small open voltage and a large short-circuit current during all-light lighting, and an open voltage greater than the open voltage in the first load characteristic during dimming lighting. It is the 2nd load characteristic of a small short circuit current.
[0063]
  The load characteristic imparting means is allowed to have the same configuration as that of the first aspect.
[0064]
    Claim2The discharge lamp lighting device of the invention is claimed in claim1The discharge lamp lighting device according to claim 1, further comprising detection means for detecting the end of life of the discharge lamp; when the detection means detects the end of life of the discharge lamp, the capacity of the capacitance connected in parallel with the discharge lamp by the capacity variable means It is characterized by making it smaller.
[0065]
  According to the present invention, the discharge lamp automatically lowers the open-circuit voltage at the end of its life so that the discharge lamp is extinguished.
[0066]
  The detection means may have any configuration as long as it can detect the end of life of the discharge lamp in response to the voltage between the electrodes of the discharge lamp, the lamp current, the power consumption of the discharge lamp, light, or the like.
[0067]
  A second aspect of the discharge lamp lighting device of the present invention will be described.
[0068]
  Second aspectIsFirst aspectThe plurality of discharge lamps have different rated power consumption.
[0069]
  Mainly, there are lighting fixtures for home use in which a discharge lamp with different rated power consumption is attached to one lighting fixture. In particular, in a ring-shaped discharge lamp, a lighting fixture in which a plurality of discharge lamps having different rated power consumptions are concentrically arranged is frequently used.
[0070]
  The present invention is applicable while using the high-frequency generating means common to the above-described lighting fixtures. Therefore, the configuration is simple and inexpensive.
[0071]
  In order to adapt the discharge lamps of different rated power consumption to the load circuit, the respective lamp currents can be optimized by adjusting the impedance of the current limiting element.
[0072]
    Claim3The illuminating device of the present invention is supported by the illuminating device main body;Or 2And a discharge lamp lighting device as described above.
[0073]
  The present invention provides a lighting device such as a lighting fixture.Or 2It has the features and actions. In the case of a lighting fixture, it adapts to any desired lighting fixtures such as home use and facility use. Moreover, any of indoor use and outdoor use may be used.
[0074]
  In the present invention, the illuminating device includes any device that utilizes light emission of a discharge lamp.
[0075]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0076]
    FIG. 1 is a block circuit diagram showing a first embodiment of a discharge lamp lighting device according to the present invention.
[0077]
  In the figure, 1 is an AC power source, 2 is a rectifier circuit, 3 is a DC-DC converter, 4 is a high frequency generating means, 5 is a load circuit, and 6 is a control means.
[0078]
  The AC power source 1, the wave rectifier circuit 2, and the DC-DC converter 3 constitute an adjustable DC power source.
[0079]
  The high frequency generating means 2 has an input end connected to the output end of the DC-DC converter 3 and has a switching means inside.
[0080]
  The load circuit 5 includes an inductance 5a, a discharge lamp 5b, and a capacitance 5c. The discharge lamp 5b and the capacitance 5c are connected in parallel and in series with the inductance 5a. The inductance 5a acts as a current limiting element, and the capacitance 5c applies a required high voltage due to resonance at the start to the discharge lamp 5b.
[0081]
  Furthermore, the load circuit 5 can impart the following load characteristics to the load circuit by appropriately setting the inductance 5a, the capacitance 5c, and the output frequency of the high frequency generating means 4.
[0082]
  That is, it has a load characteristic with a relatively small open-circuit voltage and a large short-circuit current during all-light lighting, and a load characteristic with a relatively large open-circuit voltage and a small short-circuit current during dimming lighting.
[0083]
  Therefore, in this embodiment, the inductance 5a, the capacitance 5c, and the high frequency generation means 4 constitute load characteristic provision means.
[0084]
  The control means is for setting all-light lighting and dimming lighting of the discharge lamp 5b, and switches, for example, the output frequency of the high-frequency generation means 134.
[0085]
    FIG. 2 is a graph showing the load characteristics of the load circuit in the first embodiment of the discharge lamp lighting device of the present invention shown in FIG.
[0086]
  In the figure, the horizontal axis represents the output current, and the vertical axis represents the output voltage.
[0087]
  Curve A is a curve showing the first load characteristic, and curve B is a curve showing the second load characteristic.
[0088]
  In the first load characteristic, the open circuit voltage is low, but the short circuit current is large.
[0089]
  On the other hand, in the second load characteristic, the open circuit voltage is large but the short circuit current is small.
[0090]
  Curve a is an operating characteristic curve of the discharge lamp in a normal state, and curve b is an operating characteristic curve at the end of the life.
[0091]
  When the discharge lamp is normal, the intersection X1 between the load characteristic curve A and the operating characteristic curve a is the operating point.
[0092]
  Now, when the discharge lamp reaches the end of its lifetime when all the lights are on, the operating characteristic of the discharge lamp changes as shown by the curve b and the lamp voltage becomes higher than the open circuit voltage as compared with the normal condition. It cannot intersect with the load characteristic curve A. That is, an operating point cannot be formed for the first and second load characteristics. For this reason, the discharge lamp cannot be turned on and is turned off.
[0093]
  Therefore, it is possible to avoid melting of a glass bulb, a base, a socket and the like in the vicinity of the electrode of the discharge lamp at the end of the life.
[0094]
  On the other hand, at the time of dimming lighting, the intersection point X2 between the load characteristic curve B and the operation characteristic curve a is an operation point. That is, an operating point can be formed for the second load characteristic.
[0095]
    FIG. 3 is a circuit diagram showing a second embodiment of the discharge lamp lighting device of the present invention.
[0096]
  In the figure, the same parts as those in FIG.
[0097]
  In the present embodiment, a plurality of, for example, two load circuits 5, 5 ′ are connected in parallel to the output terminal of the high frequency generator 4, and the specific circuit configuration of the DC-DC converter 3 and the high frequency generator 4 is shown. It is.
[0098]
  In the DC-DC converter 3, an inductor 3a and a diode 3b are connected in series between the input and output terminals, a switching means 3c is connected between the connection point of the inductor 3a and the diode 3b and the negative electrode, and a smoothing capacitor is connected between the output terminals. 3d is connected. Further, the voltage detection circuits 3e and 3f are connected to the input terminal and the output terminal, respectively, and the control signal of the switching means 3c is generated so as to become a constant voltage in the control circuit 3g according to the detection output. As a whole, a boost chopper is formed.
[0099]
  The high frequency generation means 4 consists of a half bridge type inverter. That is, a pair of switching means 4a and 4b are connected in series between the output terminals of the DC-DC converter 3, and are alternately turned on and off by the switching control circuit 4c. The switching control circuit 4c includes an oscillator 4c1, a reference potential source 4c2, a comparator 4c3, and an inverter 4c4. Then, the output of the oscillator 4c1 and the potential of the reference potential source 4c2 are compared by the comparator 4c3, the output is supplied to the control electrode of the switching means 4b, and the output of the comparator 4c3 is inverted by the inverter 4c4 to switch the switching means. 4a is supplied to the control electrode.
[0100]
  The load circuits 5 and 5 ′ are connected between the high-frequency output end of the high-frequency generating means 4, that is, the connection point between the switching means 4a and 4b, and the negative electrode of the DC-DC converter 3, respectively. Are connected in series.
[0101]
  The control means 6 sets all-light lighting and dimming lighting, and is configured to switch the oscillation frequency of the oscillator 4c1 of the switching control circuit 4c of the high-frequency generation means 4.
[0102]
  Thus, in the present embodiment, when one of the discharge lamps, for example, 5b reaches the end of its life, the lamp is turned off, but the remaining discharge lamp 5b 'continues to be lit in all light.
[0103]
    FIG. 4 is a circuit diagram showing a third embodiment of the discharge lamp lighting device of the present invention.
[0104]
  In the figure, the same parts as those in FIG.
[0105]
  In the present embodiment, the capacities of capacitors 5c and 5c 'connected in parallel with the discharge lamp are variable, and end-of-life detection means 7 and 7' are provided. That is, the first capacitors 5c1, 5c1 'having a relatively large capacity and the second capacitors 5c2, 5c2' having a relatively small capacity are switched by the switches 8, 8 '.
[0106]
  The end of life detecting means 7 and 7 'detects the end of life by detecting the voltage between the electrodes of the discharge lamps 5b and 5b'.
[0107]
  The switches 8, 8 'normally connect the first capacitances 5c1, 5c1' having a large capacity in parallel with the discharge lamps 5b, 5b ', but the end-of-life detection means 7, 7' are connected to the discharge lamps 5b, 5b. When the end of life of 'is detected, the capacitance is switched to the second capacitance 5c2, 5c2' having a small capacity. E is a DC power source.
[0108]
  Thus, the load circuits 5 and 5 ′ exhibit load characteristics determined by the first capacitances 5c1 and 5c1 ′ when the discharge lamps 5b and 5b ′ are normal, but when any one of the discharge lamps, for example, 5b, reaches the end of its life, Since the end-of-life detection means 7 detects this, the switch 8 opens the first capacitance 5c1 and connects the second capacitance 5c2. Thereby, the load circuits 5 and 5 ′ exhibit load characteristics determined by the second capacitances 5 c 2 and 5 c 2 ′.
[0109]
    FIG. 5 is a graph showing the load characteristics in the third embodiment of the discharge lamp lighting device of the present invention shown in FIG.
[0110]
  In the figure, the horizontal axis represents the output current, and the vertical axis represents the output voltage.
[0111]
  In the figure, a curve C is a load characteristic curve when the first capacitances 5c1, 5c1 'are connected, and a curve D is a load characteristic curve when the second capacitance 5C2 is connected. Curve c is an operating characteristic curve of a normal discharge lamp, and curve d is an operating characteristic curve at the end of life.
[0112]
  First, when the discharge lamp is normal, the lamp is lit at the intersection X between the load characteristic curve C and the operating characteristic curve c.
[0113]
  Next, when the discharge lamp, for example, 5b reaches the end of its life, the load characteristic is changed to the load characteristic curve D by connecting the second capacitance 5c2 to the load circuit 5, so the open circuit voltage is low. On the other hand, the operating characteristic of the discharge lamp changes to an operating characteristic curve d, and the lamp voltage is high, so that the intersection between the curve D and the curve d cannot be made.
[0114]
  For this reason, the discharge lamp that has reached the end of its life is extinguished.
[0115]
  On the other hand, since the other discharge lamp 5b 'remains connected to the first capacitor 5c1', it continues to be lit for the reason described above.
[0116]
    FIG. 6 is a graph showing load characteristics when the third embodiment of the discharge lamp lighting device of the present invention shown in FIG. 4 is continuously dimmed.
[0117]
  In the figure, description of the same parts as those in FIG. 5 is omitted.
[0118]
  Increasing the output frequency of the high-frequency generating means from the load characteristic curve C for all light increases the dimming degree. Along with this, the load characteristic curve shifts to C1 and C2, and the operating point shifts from X to X1 and X2, and continuous light control can be performed.
[0119]
    FIG. 7 is a graph showing load characteristics when the third embodiment of the discharge lamp lighting device of the present invention shown in FIG. 4 is switched to the second capacitance at the start and switched to the first capacitance after lighting.
[0120]
  In the figure, the description of the same part as in FIG. 5 is omitted.
[0121]
  Since the load characteristic curve C is obtained by connecting the second capacitor 5c2 at the start, a high open-circuit voltage can be applied to the discharge lamp to facilitate the start.
[0122]
  Then, after the discharge lamp is lit, the first capacitor 5c1 is connected. As a result, the load characteristic curve D is obtained, and the discharge lamp is lit at the operating point X. When the discharge lamp reaches the end of its life, as described above, the load characteristic curve D and the operation characteristic curve at the end of the life cannot intersect, so the discharge lamp is automatically turned off.
[0123]
    FIG. 8 is a circuit diagram showing a fourth embodiment of the discharge lamp lighting device of the present invention.
[0124]
  In the figure, the same parts as those in FIG.
[0125]
  This embodiment is different from FIG. 4 in the circuit configuration of capacitance switching. That is, the capacitor 5c2 is always connected in parallel with the discharge lamps 5b and 5b ', and the capacitors 5c3 and 5c3' are connected and separated by the switch 8. Therefore, when the switch 8 is closed, the capacitors 5c2 and 5c3 are connected in parallel to increase the combined capacitance, which becomes equal to the capacitance of the capacitance 5c1 in FIG.
[0126]
  On the other hand, when the switch 8 is opened, only the capacitance 5c2 is connected in parallel to the discharge lamps 5b and 5b ', so that the capacitance is reduced.
[0127]
  Thus, the action accompanying the change in capacitance is the same as that of the third embodiment of the present invention shown in FIG.
[0128]
    FIG. 9 is a circuit diagram showing a fifth embodiment of the discharge lamp lighting device of the present invention.
[0129]
  In the figure, the same parts as those in FIG.
[0130]
  This embodiment is different in load circuit. That is, three sets of load circuits 5, 5 ′, 5 ″ are connected in parallel to the common high-frequency generator 4. The discharge lamps 5 b, 5 b ′, 5 b ″ have different rated power consumption. In this case, the inductances 5a, 5a ′, 5a ″ are adjusted so that a predetermined lamp current flows.
[0131]
  Further, by appropriately setting the inductances 5a, 5a ′, 5a ″, the capacitances 5c, 5c ′, 5c ″ and the output frequency of the high frequency generating means 4, when any one of the discharge lamps reaches the end of its life, the discharge The lamp is turned off, but the remaining discharge lamps are configured to continue to be lit. A specific configuration example is as follows.
[0132]
  The output frequency of the high frequency generation means in all light is set to be sufficiently smaller than the natural resonance frequency of the load circuit. The natural resonance frequency can be set as desired by selecting the inductance and capacitance of the load circuit.
[0133]
  By setting the output frequency as described above, the capacitances 5c, 5c ′, 5c ″ connected in parallel with the discharge lamp do not resonate, and the inductances 5a, 5a ′, 5a ″ act as simple impedances. The open circuit voltage becomes low. In this case, the open circuit voltage is almost determined by the output voltage of the high frequency generating means.
[0134]
    FIG. 10 is a circuit diagram showing a sixth embodiment of the discharge lamp lighting device of the present invention.
[0135]
  In the figure, the same parts as those in FIG.
[0136]
  This embodiment is different in that a plurality of discharge lamps of load circuits 5 and 5 'are connected in series. That is, two discharge lamps 5b1, 5b2, 5b1 'and 5b2' are connected in series to each load circuit 5 and 5 ', and capacitances 5c and 5c' are connected in parallel with both discharge lamps. Capacitors 5h and 5h ′ for sequential starting are connected in parallel with the lamps 5b1 and 5b1 ′.
[0137]
  Then, when the high frequency output of the high frequency generating means 4 is applied to the load circuit 5, 5 ', all voltages are first applied across the discharge lamps 5b2, 5b2' via the capacitances 5d, 5d ', 5d ". Next, since voltage is intensively applied across the discharge lamps 5b1, 5b1 ', the discharge lamps 5b1, 5b1' are subsequently started and lit. This is the same as the so-called sequential starting type.
[0138]
    FIG. 11 is a circuit diagram showing a seventh embodiment of the discharge lamp lighting device of the present invention.
[0139]
  In the figure, the same parts as those in FIG.
[0140]
  This embodiment is different in that the output frequency of the high-frequency generating means 4 is lowered at the end of life. That is, the lamp voltage detection means 9 and 9 ′ are connected in parallel to the discharge lamps 5b and 5b ′, and the output thereof is input to the determination means 10 to determine the end of life, and the frequency switching means 11 is operated at the end of life. To switch the oscillation frequency of the oscillator 3c1.
[0141]
  Thus, when the discharge lamp, for example, 5b reaches the end of its life, the oscillation frequency of the oscillator 3c1 is switched low via the lamp voltage detection means 9, the determination means 10 and the frequency switching means 11, so that the switching means of the high frequency generation means 3 The frequency decreases and the output frequency of the high frequency generating means 3 decreases. As a result, it is apparent from the above description that the open-circuit voltage is lowered and the discharge lamp 5b at the end of life is extinguished.
[0142]
    FIG. 12 is a conceptual diagram showing an embodiment of a lighting device according to the present invention.
[0143]
  The present embodiment is a ceiling-mounted lighting fixture for home use using thin tube-type discharge lamps 5b1 and 5b2.
[0144]
  In the figure, 12 is a chassis, 13 is a reflector, 14 is a lighting device, and 15 is a translucent cover.
[0145]
  The chassis 12 has a circular shallow dish shape, has a means for attaching to the ceiling, and has a mechanism for mounting the translucent cover 15.
[0146]
  The reflection plate 13 is formed as shallow as possible and is shaped to reflect the light emitted from the discharge lamps 5b1 and 5b2 so that the luminance of the surface of the translucent cover 15 is as uniform as possible.
[0147]
  The lighting device 14 includes a load circuit excluding the discharge lamp, a high-frequency generation unit, and a DC power source, and is disposed in a space formed between the chassis 12 and the reflection plate 13.
[0148]
  The translucent cover 15 is disposed on the lower surface of the chassis 12 and surrounds the discharge lamps 5b1 and 5b2, the reflection plate 13, and the like.
[0149]
  By the way, the discharge lamps 5b1 and 5b2 are thin tubes having a tube outer diameter of 16.5 mm, and ring-shaped fluorescent lamps are used. This fluorescent lamp has model names FHC27 and FHC34, and the lighting device 14 is configured so that each of the fluorescent lamps is lit at a high output of 34 W and 48 W in all-light lighting.
[0150]
  Thus, the lighting fixture of the present embodiment has a tube outer diameter of 29 mm as described above, while the conventional general fluorescent lamp has a tube outer diameter of 16.5 mm. Because it can be made smaller and can be made very thin, there is no feeling of pressure even if it is installed in a room with a relatively low ceiling height as seen in apartments. Also, the rated life is 9000 hours compared with 6000 hours for a general-type fluorescent lamp, and thus the rated life is 1.5 times longer. Furthermore, as described above, there is no fear of melting due to an abnormal temperature rise at the end of life, which is likely to pose a serious problem in a conventional thin tube discharge lamp.
[0151]
【The invention's effect】
    Claim 1And 2According to the inventions, the load circuit has a first open circuit voltage lower than a lamp voltage at the end of the life of the discharge lamp and a relatively large short-circuit current when all the lights are turned on or when all the lights and the electrodes are preheated. The load characteristic of the first load characteristic is large compared to the open circuit voltage in the first load characteristic, and the short circuit current is small compared to the short circuit current in the first load characteristic. A discharge lamp that exhibits the second load characteristic and is normal with respect to the first and second load characteristics can form an operating point, but a discharge lamp at the end of its life cannot form an operating point.In addition, the capacitance of the capacitance connected in parallel with the discharge lamp can be varied.By being configured, glass bulbs, caps, sockets, etc. can be melted by turning off the discharge lamp at the end of its life without using a complicated protection circuit, even for a thin tube discharge lamp. Prevent, and if desired, make a good and smooth startAt the same time, the load characteristics can be changed as desired to ensure protective operation at the end of life.A discharge lamp lighting device can be provided.
[0152]
    Claim2According to the invention, in addition, it is possible to provide a discharge lamp lighting device that automatically and reliably performs a protection operation by switching the capacitance of the capacitance connected in parallel with the discharge lamp in accordance with the output of the end of life detection means. .
[0153]
    Claim3According to the invention of claim 1,And 2It is possible to provide a lighting device having the following effects.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a first embodiment of a discharge lamp lighting device according to the present invention.
FIG. 2 is a graph showing load characteristics of a load circuit in the first embodiment of the discharge lamp lighting device of the present invention shown in FIG.
FIG. 3 is a circuit diagram showing a second embodiment of a discharge lamp lighting device according to the present invention.
FIG. 4 is a circuit diagram showing a third embodiment of a discharge lamp lighting device of the present invention.
FIG. 5 is a graph showing load characteristics in the third embodiment of the discharge lamp lighting device of the present invention shown in FIG. 4;
6 is a graph showing load characteristics when the third embodiment of the discharge lamp lighting device of the present invention shown in FIG. 4 is continuously dimmed.
FIG. 7 is a graph showing load characteristics when the third embodiment of the discharge lamp lighting device of the present invention shown in FIG. 4 is switched to the second capacitance at start-up and then switched to the first capacitance after lighting.
FIG. 8 is a circuit diagram showing a fourth embodiment of a discharge lamp lighting device according to the present invention.
FIG. 9 is a circuit diagram showing a fifth embodiment of a discharge lamp lighting device of the present invention.
FIG. 10 is a circuit diagram showing a sixth embodiment of the discharge lamp lighting device of the present invention.
FIG. 11 is a circuit diagram showing a seventh embodiment of the discharge lamp lighting device of the present invention.
FIG. 12 is a conceptual diagram showing an embodiment of a lighting device according to the present invention.
FIG. 13 is a circuit diagram showing a discharge lamp lighting device according to prior art 1;
FIG. 14 is a graph showing load characteristics of a load circuit in Conventional Technology 1
[Explanation of symbols]
      1 ... AC power supply
      2 ... Rectifier circuit
      3 ... DC-DC converter
      4. High frequency generation means
      5 ... Load circuit
      5a: Inductance
      5b ... discharge lamp
      5c: Capacitance
      6. Control means

Claims (3)

Discharge lamp, a discharge lamp and viewed including the series connected inductance and a discharge lamp and connected in parallel capacitance, the total light lit or Zenhikariji and electrode preheating time to the discharge lamp end of life time of the lamp voltage lower open circuit voltage than And a first load characteristic having a relatively large short-circuit current, a large open-circuit voltage compared to the open-circuit voltage in the first load characteristic at the time of dimming lighting or at the time of dimming and starting, Although the discharge lamp in the normal state exhibits a second load characteristic with a small short-circuit current as compared with the short-circuit current in the load characteristic, and can operate at a normal time with respect to the first and second load characteristics, A load circuit configured so that the discharge lamp at the end stage cannot form an operating point ;
High frequency generating means for supplying high frequency output to the load circuit;
Control means for setting all-light lighting and dimming lighting;
Capacity changing means for changing the capacity of the capacitance connected in parallel with the discharge lamp;
A discharge lamp lighting device comprising: Comprising detection means for detecting the end of life of the discharge lamp;
When the detecting means detects the end of life of the discharge lamp, the capacity of the capacitance connected in parallel with the discharge lamp is reduced by the capacity changing means;
The discharge lamp lighting device according to claim 1 . A lighting device body;
The discharge lamp lighting device according to claim 1 or 2 , supported by a lighting device body;
An illumination device comprising:

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