JP2007157335A - State determination method of discharge lamp, discharge lamp lighting device, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a state determination method of a discharge lamp which is not limited by the type of a filament, and thus easy to be measured. <P>SOLUTION: When a voltage detecting means 9 detects that a lamp voltage is rapidly lowered, and further lowered to a previously set predetermined value, a warm resistance value Rh of the filament is obtained from a detection value of a filament voltage detecting means 5 at that time and a current value of a power supply 3 as a constant current source. A ratio Rh/Rc of the warm resistance value Rh and a previously measured cold resistance value Rc is obtained (Fig. 2). A similar test is conducted with a filament in a life end state, and shown in Fig. 3. It is found that a phenomenon that the Rh/Rc rapidly increases occurs when an emitter surface area decreases to a certain level irrespective of the specification of the filament. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for determining a deterioration state of a discharge lamp from a filament state, a discharge lamp lighting device for lighting a hot cathode discharge lamp, and an illumination device.

  Most hot-cathode discharge lamps reach the end of their lives due to exhaustion of the filament emitters. When a discharge lamp with no emitter is continuously turned on, the filament temperature rises excessively, and the stem at the end of the arc tube may melt or the arc tube may be damaged. In such a case, there is a concern that the discharge lamp may be accidentally dropped from the appliance.

  Further, if the discharge lamp with no emitter is continuously lit, the lighting device is overloaded and the lighting device may be damaged.

  In order to solve such a problem, the applicant of the present application has proposed a discharge lamp lighting device that can determine that the discharge lamp has reached the end of its life before the above-described problem occurs (Patent Document 1).

A method for inspecting the life of a discharge lamp in a non-destructive manner has also been proposed (Patent Document 2).
JP 2004-221027 A Japanese Patent No. 3314463

  Patent Document 1 discloses that the time required for the ratio (Rh / Rc) of the cold resistance value (Rc) to the preheated temperature resistance value (Rh) to reach a preset predetermined value is a preset allowable minimum time. If it is less than, it will be judged as the end of life.

  However, Patent Document 1 is not sufficient in that it is difficult to cope with various discharge lamps. In other words, the type of discharge lamp that is lit by a kind of lighting device is often not one. For example, recent fluorescent lamp lighting devices include a plurality of types of fluorescent lamps such as FL40, FLR40, and FHF32 that are to be lit. Even with FL40, the filament design differs depending on the manufacturer. For this reason, the ratio (Rh / Rc) between the cold resistance value (Rc) and the preheated resistance value (Rh) varies depending on the type and manufacturer of the discharge lamp. However, in the case of Patent Document 1, it is difficult to properly determine the end of life of various filaments because the specification of the filament (the relationship between the temperature resistance value Rh and the remaining amount of emitter, etc.) cannot be handled in advance. It is.

  The method of Patent Document 2 measures the amount of emitter lost by calculating the energy balance of the emitter of the filament.

  However, in Patent Document 2, only the amount of disappearance of the filament emitter can be measured, and the life of the filament and hence the life of the discharge lamp cannot be estimated. That is, since the initial amount of emitter is unknown, it is impossible to determine whether the filament is in a life state even if the amount of disappearance of the emitter can be measured. Even if the initial emitter amount is measured, the measurement itself is not easy, and even if measurement is possible, the initial emitter amount differs depending on the individual filament specifications as described above. There is a problem in that an initial filament that becomes a reference value must be measured for each discharge lamp having different filaments.

  It is an object of the present invention to provide a method for determining the state of a discharge lamp that is less restricted by the type of filament and is therefore easy to measure.

  It is another object of the present invention to provide a discharge lamp lighting device and a lighting device that are less restricted by the type of the discharge lamp and the like and can determine the deterioration state of the discharge lamp or estimate the cumulative lighting time.

  A method for determining a state of a discharge lamp according to claim 1 includes: preheating a filament of a hot cathode type discharge lamp; generating a discharge for passing a minute discharge current between a pair of filaments; and a lamp voltage of the discharge lamp. Detecting a decrease in the lamp voltage to a predetermined value; detecting a filament resistance value when the lamp voltage decreases; and determining a deterioration state of the discharge lamp according to the filament resistance value; It is characterized by having.

  In principle, the discharge lamp state determination method according to claim 1 and the discharge lamp lighting device described below are arranged in accordance with the filament temperature at the time when the thermoelectron current from the filament is sufficiently obtained. The degree of wear and thus the deterioration state of the discharge lamp is determined. That is, when the filament is preheated, thermionic electrons are emitted. However, in a state where the wear of the emitter is slight, when the filament is heated to about 600 ° C. or more, the thermionic current sufficient for arcing the discharge lamp is obtained. It is known to be released. The thermoelectron current at this time is several mmA according to the Richardson Dashman equation.

  The temperature of the filament that emits thermionic current sufficient for such arc discharge does not change much during the life of the discharge lamp, but when it approaches the end of its life (when the wear of the emitter becomes severe), it will be sufficient if it is not heated more than before. It was found that thermionic electron current could not be obtained. The reason for this is thought to be that the temperature of the filament needs to be increased accordingly because the surface area of the filament where the emitter remains is reduced due to wear of the emitter.

  Therefore, if the temperature of the filament at the time when a thermionic current sufficient for arc discharge is released can be detected, the deterioration state of the discharge lamp (the degree of wear of the emitter) can be determined. However, it is very difficult to directly detect the thermionic current and the filament temperature in a discharge lamp lighting device that is mass-produced and requires low cost.

  In the present invention, the above determination is realized by indirectly detecting the time when the thermoelectron current is emitted by the lamp voltage and the filament temperature by the resistance value of the filament.

  In the present invention and the following invention, the order of the step of preheating the filament of the hot cathode type discharge lamp and the step of generating a discharge in which a minute discharge current flows between the pair of filaments is either first or simultaneously. But you can. Further, determining the deterioration state of the discharge lamp according to the filament resistance value may be the filament resistance value itself when the lamp voltage is lowered, or the filament resistance value (temperature resistance value when the lamp voltage is lowered). Rh) may be in accordance with the ratio of the resistance value (cold resistance value Rc) measured in advance or measured prior to the test for determination.

  In addition, the predetermined value for detecting that the lamp voltage has decreased needs only to be able to detect that the lamp voltage has rapidly decreased, and it is not necessary to set a strict boundary.

  A discharge lamp lighting device according to claim 2 is a variable output lighting device capable of supplying filament preheating power and lighting power to a hot cathode discharge lamp; resistance detection means for detecting a resistance value of the filament; Filament resistance value when the output of the lighting device is controlled to preheat the filament and allow a small discharge current to flow, and the lamp voltage is detected during this control period, and the lamp voltage drops to a preset value. And a control means for determining the deterioration state of the discharge lamp according to the above.

  In the invention described in claim 2 and the following invention, the definitions or technical meanings of terms are as follows. The hot-cathode discharge lamp has a preheated filament and can be used for general lighting, sterilization, decoration, etc. Any shape such as a so-called compact shape may be used.

  The lighting device may be an iron / copper type or an electronic type, but an electronic type is advantageous in that the output can be easily changed. For example, an inverter type inverter having a switching device that switches at high frequency and a resonance circuit can easily change the output value by changing the switching frequency, the on-duty of switching, or the input DC voltage value. Is possible. However, the present invention is not limited to the inverter type, and the above-described iron / copper type or other types may be used as long as the output can be changed as defined by the present invention.

  Any resistance detecting means may be used as long as it can detect the resistance value. In terms of cost, it is most advantageous to calculate the filament resistance value from the detected values of the filament current detection means and the filament end-to-end voltage detection means. In this case, both detection values can be converted from analog to digital and processed by an IC, a microcomputer, and a DSP (digital signal processor).

  The reason why a very small discharge current is allowed to flow through the discharge lamp is that the cathode fall voltage is large during the glow discharge period of the discharge lamp, so that a large discharge current increases the power loss and the wear of the emitter. . About a very small degree, in the said FL40 class discharge lamp, it is 10 mA or less, Preferably it is 5 mA or less. Generally, it is 1/10 to 1/100 of the rated lamp current. Further, a minute current may be allowed to flow intermittently, or may be allowed to flow after the filament has risen in temperature by preheating to some extent. Furthermore, it is preferable that the life determination according to the present invention is performed intermittently, such as once every several times or once every several tens of times, not every start. In order to perform such fine control, it is preferable to use the microcomputer and the DSP (digital signal processor).

  According to the second aspect of the present invention, the filament of the discharge lamp is preheated and a dielectric breakdown voltage is applied between the pair of filaments to cause discharge, thereby allowing a minute discharge current to flow. In the initial stage, since the filament is not sufficiently heated, the emission of thermoelectrons is insufficient and the lamp voltage is high. When the temperature of the filament gradually rises and reaches a sufficient thermoelectron emission temperature, thermoelectrons are emitted and the lamp voltage decreases rapidly. When the lamp voltage reaches a predetermined value set in advance, the filament resistance value at that time is detected. The deterioration state of the discharge lamp is determined according to the detected value. For example, when the resistance value of the filament is greater than or equal to a predetermined value, it is determined that the discharge lamp has reached the end of its life and the operation of the lighting device is stopped. However, the cumulative lighting time of the discharge lamp may be estimated based on the determination result of the deterioration state.

  According to a third aspect of the present invention, in the discharge lamp lighting device according to the second aspect of the present invention, the control means sets the ratio between the cold resistance value of the filament and the filament resistance value when the discharge voltage is lowered to a predetermined value set in advance. Accordingly, the deterioration state of the discharge lamp is determined.

  Since the present invention determines the deterioration state of the discharge lamp according to the ratio between the cold resistance value of the filament and the filament resistance value when the discharge voltage drops to a predetermined value set in advance, the determination error due to the specification and variation of the filament Can be further reduced. In this case, if the cold resistance value is measured for each determination, the influence of the ambient temperature can be taken into account and the determination accuracy can be further improved.

  A discharge lamp lighting device according to a fourth aspect is characterized in that, in the invention according to the second or third aspect, the control means estimates a cumulative lighting time based on a result of determining a deterioration state of the discharge lamp.

  The cumulative lighting time means the total time when the discharge lamp is actually turned on. The cumulative lighting time is closely related to the decrease in the luminous flux emitted from the discharge lamp. Recently, a lighting device has been adopted in which the light output at the initial stage of the discharge lamp is suppressed, and the light output is increased as the cumulative lighting time elapses so that the light output is substantially constant throughout the life of the discharge lamp. In this case, a timer is generally used as a means for measuring the cumulative lighting time. However, there is a problem that a special timer is necessary and a means for resetting the timer every time the lamp is replaced is necessary. .

  The present invention estimates the cumulative lighting time based on the filament state, and does not require any special timer or timer resetting means.

  The invention of claim 5 is an illumination comprising: the discharge lamp lighting device according to any one of claims 2 to 4; and a lighting fixture main body provided with a discharge lamp that is lit by the discharge lamp lighting device. Device.

  According to claim 1, it is possible to provide a discharge lamp state determination method capable of determining the deterioration state of the discharge lamp regardless of the specification of the filament.

According to the second to fourth aspects of the invention, it is possible to provide a discharge lamp lighting device that can easily determine the deterioration state of the discharge lamp regardless of the type of the discharge lamp.

  According to the fifth aspect of the present invention, it is possible to provide an illumination device including the discharge lamp lighting device according to the second to fourth aspects of the present invention.

  Hereinafter, a first embodiment of a discharge lamp state determination method according to the present invention will be described with reference to FIGS. 1 is a circuit diagram showing the configuration of a test circuit, FIGS. 2 and 3 are diagrams showing the relationship between time, lamp voltage, and filament resistance, and FIG. 4 is a diagram showing the relationship between emitter coating area and filament resistance in a filament. FIG.

  The test circuit includes a power source 3 for supplying a filament preheating current to one filament 2 of a hot cathode type discharge lamp 1. The power source 3 is, for example, a constant current power source. 4 is a switch for controlling on / off of the power source 3, and 5 is a voltage detection means for detecting the voltage across the filament 2.

  A power source 6 for generating a glow discharge by flowing a minute current through the discharge lamp 1 is provided between the both ends of the discharge lamp 1 via a switch 7 and a current limiting resistor. Reference numeral 9 denotes voltage detection means for detecting the lamp voltage of the discharge lamp 1.

  In this test circuit, first, the switch 4 is closed and preheating of the filament 2 is started. Next, the switch 7 is closed to cause the discharge lamp 1 to glow discharge, and a minute discharge current flows. During this time, the voltage detection means 5 and 9 detect the filament voltage and the lamp voltage, respectively.

  When the filament 2 rises in temperature due to preheating, it emits thermoelectrons, and the discharge voltage (lamp voltage) drops rapidly as shown in FIG. 2 and 3, the horizontal axis represents time, the left vertical axis represents the discharge voltage (lamp voltage), and the right vertical axis represents the ratio between the cold resistance value (Rc) and the thermal resistance value (Rh) of the filament 2. (Rh / Rc) is shown. FIG. 2 shows a test result when the filament 2 is in the initial state, and FIG. 3 shows a test result when the remaining amount of the emitter of the filament is small and in the end-of-life state.

  When the voltage detection means 9 detects that the lamp voltage has suddenly dropped to a predetermined value (for example, 200 V) set in advance, the detected value of the filament voltage detection means 5 at this time and the power source that is a constant current source From the current value of 3, the temperature resistance value (Rh) of the filament is obtained. Then, a ratio (Rh / Rc) between the temperature resistance value (Rh) and the cold resistance value (Rc) measured in advance is obtained. In the case of the filament in the initial state of FIG.

  On the other hand, when the filament was tested in the same manner at the end of life, (Rh / Rc) was about 5, as shown in FIG.

  FIG. 4 shows the relationship between (Rh / Rc) obtained by performing the above test while changing the amount of emitter of the filament (emitter surface area on the filament base material such as tungsten). As is clear from FIG. 4, it was found that (Rh / Rc) suddenly increased from a certain point as the emitter surface area decreased. The present inventor has confirmed that the phenomenon that (Rh / Rc) rapidly increases occurs when the emitter surface area is reduced to a certain extent regardless of the specification of the filament.

  Therefore, according to this discharge lamp state determination method, it is possible to determine the deterioration state regardless of the type of filament and the type of discharge lamp.

Next, an embodiment of a discharge lamp lighting device according to the present invention will be described with reference to FIG. FIG. 5 is a circuit diagram showing an embodiment of a discharge lamp lighting device.

  A lighting device 21 composed of a half-bridge type high-frequency inverter circuit is connected to the DC power supply device 20. The lighting device 21 connects a series circuit of a pair of MOS FETs 22 and 23 to the DC power supply device 20 as a switching element. The pair of FETs 22 and 23 are alternately turned on and off in response to a signal from the driving means 24 to switch the output voltage of the DC power supply device 20. A series circuit of a DC cut capacitor 25, a resonance and current limiting inductor 26, and a hot cathode discharge lamp 27, which is a fluorescent lamp, is connected in parallel with the drain / source of one FET 23. A resonance and starting capacitor 28 is connected between a pair of filaments on the non-power supply side of the discharge lamp 27. The inductor 26 and the resonance capacitor 28 form a series resonance circuit, which is supplied with a high-frequency switching output and outputs a resonance voltage. Therefore, the series resonant circuit can change its output according to the switching frequency.

  One filament is provided with a filament voltage detection means 30 for detecting the voltage of the filament, and a current detection means 31 for detecting a current flowing through the filament is provided between the pair of filaments on the non-power supply side. In parallel with the discharge lamp 27, lamp voltage detection means 32 for detecting the lamp voltage is provided. The outputs of the detection means 30, 31, 32 are input to an analog / digital converter 33, and the output of the analog / digital converter 33 is input to a calculation means 34.

  The calculation means 34 is configured by an IC, a microcomputer, a digital signal processor, and the like, and includes a calculation unit 34a, a storage unit 34b, a time measuring unit 34c, and an interface 34d. And the calculating means 34 calculates the output of each said detection means 30,31,32, calculates | requires and memorize | stores a filament resistance value. Therefore, in the present embodiment, the resistance detection means is formed by the filament voltage detection means 30, the current detection means 31, and the calculation means 34.

  The computing means 34 has a function of controlling the driving means 24 of the lighting device 2 and changing the frequency of the output signal.

  Next, the operation of this embodiment will be described. First, the output of the lighting device 2 is controlled so as to generate a discharge in which a minute discharge current flows between a pair of filaments of the discharge lamp 27 while preheating the filament of the hot cathode discharge lamp 27. And if a filament raises and discharge | releases a thermoelectron, the lamp voltage of the discharge lamp 27 will fall rapidly similarly to the tendency shown in FIG. Such a lamp voltage is detected by the lamp voltage detection means 32 and input to the calculation means 34. When the voltage detecting means 32 detects that the lamp voltage of the discharge lamp 27 has dropped rapidly, the calculating means 34 calculates the filament resistance value at that time. That is, the filament resistance value is obtained by dividing the filament voltage value by the filament current value. And the deterioration state of the discharge lamp 27 is determined according to some filament resistance values. In the present embodiment, the ratio (Rh) / (Rc) between the temperature resistance value (Rh) when the lamp voltage rapidly decreases and the cold resistance value (Rc) before starting the preheating or at the time of starting the preheating is obtained. Accordingly, the deterioration state is determined.

  For example, if the discharge lamp 27 is determined to have a life based on the determination result of the deterioration state, the operation of the lighting device 21 is stopped, that is, the output of the driving unit 24 is stopped, and the discharge lamp 27 is not started and lit.

  Further, when it is determined that the light output has decreased according to the cumulative lighting time, although the discharge lamp 27 is not at the end of its life, the output of the driving unit 24 is controlled to compensate for the light output decrease. Thus, the output of the lighting device 21 is controlled.

  Next, an embodiment of a lighting device according to the present invention will be described with reference to FIG. In the case of FIG. 6, the lighting device is a ceiling-mounted lighting fixture. 60 is a lighting fixture body, 61 is a socket provided in the lighting fixture body 60, 62 is a reflector, 63 is a hot cathode discharge lamp mounted on the socket 61, and 64 is a discharge lamp built in the lighting fixture body 60. It is a lighting device.

  The illuminating device having such a configuration can estimate the end of life or the cumulative lighting time of the filament and thus the discharge lamp 63, thereby causing inconvenience and unexpected turn-off due to continuous lighting of the discharge lamp 63 in the end-of-life state. Less.

The circuit diagram which shows the structure of one test circuit of the state determination method of the discharge lamp by this invention The figure which shows the relationship between time of the test result and lamp voltage, filament resistance value, A graph showing the relationship between the test result time, lamp voltage, and filament resistance FIG. 4 is a diagram showing the relationship between the emitter coating area and the filament resistance value in the filament. The circuit diagram which shows one Embodiment of the discharge lamp lighting device by this invention The perspective view which shows one Embodiment of the illuminating device by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... High frequency inverter circuit, 3, 4 ... MOS type FET, 6 ... Inductor, 7 ... Discharge lamp, 8 ... 2nd capacitor, 13 ... CPU, 18 ... Memory, 21 ... Sine wave voltage source, 22 ... Triangular wave signal source, 23 ... Comparator.

Claims (5)

Preheating the filament of a hot cathode discharge lamp;
Generating a discharge for passing a minute discharge current between a pair of filaments;
Detecting that the lamp voltage of the discharge lamp drops to a predetermined value set in advance;
Detecting a filament resistance value when the lamp voltage decreases;
Determining the deterioration state of the discharge lamp according to the filament resistance value;
The state determination method of the discharge lamp characterized by comprising. A variable output lighting device capable of supplying filament preheating power and lighting power to a hot cathode discharge lamp;
Resistance detection means for detecting the resistance value of the filament;
When preheating the filament of the discharge lamp and controlling the output of the lighting device so that a minute discharge current flows, and detecting the lamp voltage during this control period, when the lamp voltage drops to a predetermined value set in advance Control means for determining the deterioration state of the discharge lamp according to the filament resistance value;
A discharge lamp lighting device comprising:   The discharge lamp lighting device according to claim 2, wherein the control means determines the deterioration state of the discharge lamp according to a ratio between a cold resistance value of the filament and a filament resistance value when the discharge voltage is lowered to a predetermined value set in advance. .   4. The discharge lamp lighting device according to claim 2, wherein the control means estimates a cumulative lighting time based on a deterioration state of the discharge lamp. A lighting fixture body;
A hot cathode discharge lamp mounted on the luminaire body;
The discharge lamp lighting device according to any one of claims 2 to 4, wherein the discharge lamp is turned on;
An illumination device comprising:

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