JP4222429B2 - High pressure discharge lamp lighting device - Google Patents

Description

  The present invention relates to a high-pressure discharge lamp lighting device for high-frequency lighting of a high-pressure discharge lamp.

  FIG. 9 shows a circuit configuration diagram of a conventional high pressure discharge lamp lighting device. In FIG. 9, 1 is a DC power source, 2 is a half bridge circuit composed of a first switching element 2a and a second switching element 2b for converting a DC voltage of the DC power source 1 into a high frequency voltage, and 3 is a half bridge circuit 2. A control circuit for controlling ON / OFF driving of each switching element constituting the above, 4 is a load circuit including a resonance capacitor 5 and a choke coil 6 and a starting circuit 7, and 8 is a high frequency by supplying a high frequency voltage output from the load circuit 4. It is a high pressure discharge lamp that lights up.

  The high pressure discharge lamp lighting device having such a configuration drives and controls each switching element so that a high frequency voltage having a frequency of 1 kHz or more is supplied to the high pressure discharge lamp 8 via the load circuit 4 by the control circuit 3. In addition, the control circuit 3 controls the lighting frequency of the high-pressure discharge lamp 8 in order to prevent the occurrence of the acoustic resonance phenomenon of “disappearance” or “fluctuation” accompanying the curvature of the discharge arc in the arc tube of the generally known high-pressure discharge lamp 8. Each switching element is driven and controlled by determining a non-resonance frequency at which no acoustic resonance phenomenon occurs.

  As described above, the conventional high pressure discharge lamp lighting device employs a configuration in which the lighting frequency is determined to be a non-resonant frequency and the high pressure discharge lamp is lit. However, it is generally known that in a high pressure discharge lamp, the non-resonant frequency band also changes as the speed of sound waves in the arc tube changes according to the cumulative lighting time or when the electrodes are consumed. The high-pressure discharge lamp causes an acoustic resonance phenomenon of “disappearance” or “fluctuation” with the curvature of the discharge arc in the arc tube due to the various factors described above, and the lighting state of the high-pressure discharge lamp cannot be stably maintained. Had problems.

  The present invention has been made to solve the above-described problems. Even when the non-resonant frequency is changed due to the various factors described above, the discharge arc in the arc tube always “disappears” or “fluctuates”. The present invention provides a high pressure discharge lamp lighting device that stably operates a high pressure discharge lamp at a high frequency.

A high pressure discharge lamp lighting device according to the present invention includes a high pressure discharge lamp, tube voltage detection means for detecting a tube voltage of the high pressure discharge lamp, high frequency power supply means for supplying high frequency power to the high pressure discharge lamp, and the high frequency power. And a control circuit for controlling the frequency of the high-frequency power supplied from the supply means, and the high-pressure discharge lamp is preliminarily provided by a specific frequency range having a voltage range in the vicinity of a saturation voltage during stable lighting and a non-resonant region in the voltage range. In the high pressure discharge lamp lighting device that stably lights in a predetermined area, the control circuit supplies high-frequency power outside the specific frequency range at the time of stable lighting at the start of lighting , and the rise of the tube voltage until stable lighting. Accordingly , the lighting frequency is changed so that the lighting frequency falls within the non-resonant region.

According to the high-pressure discharge lamp device according to the present invention, the high-pressure discharge lamp can be stably lit by suppressing the resonance phenomenon associated with the curve of the discharge arc in the arc tube of the high-pressure discharge lamp from the time when the luminous flux rises until stable lighting. Can do.

Embodiment 1 FIG.
The high-pressure discharge lamp usually has a characteristic that the discharge by the enclosed argon gas continues for about 30 seconds after the lighting is started, and thereafter a metal component such as mercury starts to evaporate and the tube voltage rapidly increases.

  The present invention relates to a control method in a case where a lighting frequency that reaches an area where an acoustic resonance phenomenon occurs with a rise in tube voltage after discharge by argon gas is set at the start.

  FIG. 1 shows a circuit configuration of a high pressure discharge lamp lighting device according to the present embodiment. In FIG. 1, a difference from the conventional example is that a tube voltage detection circuit 9 for detecting the tube voltage of the high-pressure discharge lamp 8 is provided, and a non-resonance frequency at which no acoustic resonance phenomenon occurs is extracted from the detection value of the tube voltage detection circuit 9. The control circuit 10 for controlling the driving frequency of the switching elements 2a and 2b constituting the half bridge circuit 2 is provided so that the lighting frequency matches the frequency, and the resonance intensity detection circuit 11 is further provided. is there.

  FIG. 2 specifically shows the relationship between the lighting frequency, tube voltage, and acoustic resonance phenomenon generated thereby for a metal halide high pressure discharge lamp having a ceramic arc tube with a rated power of 35 W. As shown in the figure, each region is divided into A, B, C, D, E, F, and G depending on whether or not an acoustic resonance phenomenon occurs and how strong it is.

Here, a region where the acoustic resonance phenomenon occurs and a region where the acoustic resonance phenomenon does not occur are referred to as “resonance region” and “non-resonance region”, respectively. The resonance region is divided into three levels of intensity, medium and weak depending on the strength of resonance.
First, in the “strength resonance region”, the discharge arc shakes violently and disappears.
Also, in the “medium resonance region”, the probability that the discharge arc fluctuates but disappears is low. These two resonance regions can be regarded as regions where lighting itself is not established.

Furthermore, in the “weak resonance region”, the acoustic resonance phenomenon hardly occurs, but the discharge arc is not completely stable and may flicker.
Therefore, it is not a problem when the “weak resonance region” is used in a place where the luminous flux rises, but it is inappropriate to use it as a region during stable lighting because it may give the user a sense of discomfort. .

  Under such a classification, the region A is a region occupied by the discharge of argon gas whose tube voltage is from 0 V to about 50 V, and is a “non-resonant region”. The regions B, C, D, E, F, and G are all regions where the tube voltage is about 50 V or more, and are arranged in this order from the lowest lighting frequency. These correspond to “intensity resonance region”, “non-resonance region”, “weak resonance region”, “medium resonance region”, “non-resonance region”, and “intensity resonance region”, respectively.

  Further, in these regions B to G, the boundary line between adjacent regions shows a characteristic that the frequency decreases as the tube voltage increases.

  In the case of FIG. 2, the boundary lines of the region B and the region C, the region C and the region D, the region D and the region E, the region E and the region F, and the region F and the region G are (31 KHz, 50 V) and (32. 5KHz, 50V), (44.5KHz, 50V), (46KHz, 50V), and (49.5KHz, 50V) are approximated by a straight line having an inclination (−0.17 KHz / V).

  The reason why the boundary line exhibits such a characteristic that the frequency decreases as the tube voltage increases is considered as follows.

  In general, it is known that if the frequency at which the acoustic resonance phenomenon occurs is fr, the frequency fr is proportional to the product of the sound velocity in the arc tube and the shape factor of the arc tube.

  On the other hand, it is known that the speed of sound is proportional to the 1/2 power of (absolute temperature T) / (average molecular weight M) when the average molecular weight and absolute temperature of the gas sealed in the tube are represented by M and T, respectively. .

  Here, when the rate of change in absolute temperature T at the time of rising is compared with the rate of change in average molecular weight M, the metal components such as mercury, sodium, thallium, scandium, dysprotium, etc. enclosed are discharged after the discharge with argon gas. Because of vaporization, the average molecular weight M increases rapidly and greatly exceeds the absolute temperature T in terms of rate of change. This means that (absolute temperature T) / (average molecular weight M) decreases and frequency fr decreases after the discharge with argon gas. As a result, as shown in FIG. 2, the boundary line shows a characteristic that the frequency decreases as the tube voltage increases.

  Further, the tube voltage starts to increase from the start, and if it does not pass through the medium or strong resonance region, it continues to increase and reaches a saturation voltage that does not increase any more. In FIG. 2, Vs indicates a voltage range (75 to 82 V) in which such a saturation voltage falls. In addition, the frequency range (41 to 45 KHz) where the region F (non-resonant region) is cut is represented by fs by the voltage range Vs.

  In order to light the high pressure discharge lamp stably without flickering, it is important to control the tube voltage and the lighting frequency so as to fall within the region surrounded by the voltage range Vs and the frequency range fs. In this regard, L1 indicates a trajectory followed by the operating point given by the tube voltage and the lighting frequency of the high-pressure discharge lamp lighting device according to the present embodiment.

Next, the operation will be described with reference to FIGS.
The lighting frequency f1 at the start is arbitrarily set in the vicinity of the frequency range fs. In the present embodiment, the tube voltage is changed from the region A (non-resonant region) to the region D (weak resonance region). A case will be described in which the frequency to be shifted to the region E (medium resonance region) is set.

  First, the control circuit 10 drives and controls the switching elements 2a and 2b at the frequency f1 at the start of lighting, and maintains this frequency f1 until a switching signal is received from the resonance intensity detection circuit 11.

  The tube voltage detection circuit 9 detects the effective value or peak value of the tube voltage by converting it into a direct current, and inputs the detected value to the resonance intensity detection circuit 11. When the flicker resulting from the fluctuation of the discharge arc of the high-pressure discharge lamp occurs, the tube voltage converted to direct current vibrates in synchronization therewith.

  In the case of the present embodiment, as the tube voltage increases, the process proceeds from region D (weak resonance region) to region E (medium resonance region) (near the boundary between region D and region E). Flickering starts from the time when you do.

  On the other hand, the resonance intensity detection circuit 11 calculates the amplitude of the voltage fluctuation of the tube voltage converted to DC, and when the amplitude exceeds a predetermined value, the fluctuation of the discharge arc due to the acoustic resonance phenomenon is greater than a predetermined value. It is determined that the frequency f1 output from the control circuit 10 is increased by a predetermined width δf1.

  Therefore, this detects the vicinity of the boundary between the region D (weak resonance region) and the region E (medium resonance region), and the control circuit 10 changes the lighting frequency from the frequency f1 to the region F (non-resonance region). Switch to the new frequency f2 (= f1 + δf1) included and output. Here, the predetermined width δf1 is set to be larger than the frequency width of the region E (medium resonance region) based on the experimentally obtained region section.

  In this way, the operating point given by the tube voltage and the lighting frequency moves from region A (non-resonant region) → region D (weak resonance region) → region F (non-resonant region). It is possible to avoid the resonance region and reach the stable lighting region.

  In addition, in the vicinity of the boundary between the region D (weak resonance region) and the region E (medium resonance region), the moment when the tube voltage oscillation is detected or the moment when it passes through the region E (medium resonance region) From the viewpoint of the discharge phenomenon and the visual viewpoint, the time is sufficiently short so that the flicker does not become a problem. Although there are various methods for controlling the lighting frequency within the non-resonant region after switching the lighting frequency from f1 to f2, it is omitted because it is not related to the gist of the present invention.

  As described above, since the lighting frequency is changed in accordance with the change of the discharge state at the rising of the luminous flux to avoid the acoustic resonance phenomenon, the flicker before reaching the stable lighting can be avoided.

  Even when a predetermined time has elapsed after starting the lighting operation, the resonance intensity detection circuit 11 did not detect the vicinity of the boundary between the region D (weak resonance region) and the region E (medium resonance region). In this case, the control circuit 10 may be configured to forcibly switch the lighting frequency from f1 to f2.

  In this way, at the start, the lighting frequency f1 is set to be low, and in the region D where the acoustic resonance phenomenon hardly occurs (the weak resonance region), no acoustic resonance phenomenon occurs at the time of the rising of the light beam, or the discharge arc fluctuates. Even when it is small and difficult to detect, it is possible to reliably shift to control in a non-resonant region for stable lighting, and to ensure lighting stability. Further, erroneous detection due to a transient change in tube voltage immediately after the start of lighting can be prevented, and the acoustic resonance phenomenon can be reliably avoided.

  In the present embodiment, the tube voltage has already reached the voltage range Vs when the tube voltage reaches the vicinity of the boundary between the region D (weak resonance region) and the region E (medium resonance region). The case where only the lighting frequency is switched from f1 to f2 has been described. However, in the following embodiments, when the tube voltage reaches the vicinity of the boundary between the region D and the region E, the voltage range Vs is still reached. The case where there is not will be described.

Embodiment 2. FIG.
In the first embodiment, the control method in the case where the frequency at which the transition from the region A (non-resonance region) to the region D (weak resonance region) with the increase of the tube voltage is selected at the start has been described. In the present embodiment, a control method in the case where a frequency for transition from region A (non-resonant region) to region G (intensity resonance region) through region F (non-resonant region) is selected will be described.

  Since the circuit configuration diagram is the same as that shown in the first embodiment, a description thereof will be omitted. 3 shows a locus L2 followed by an operating point given by the tube voltage and the lighting frequency of the high-pressure discharge lamp lighting device according to the present embodiment, based on the partitioned areas A to G shown in FIG. , Written.

  Next, the operation will be described with reference to FIGS. The control circuit 10 drives and controls each switching element at the frequency f1 at the start, and maintains this frequency until the switching signal outputted from the resonance intensity detection circuit 11 is received. In the same manner as in the first embodiment, the tube voltage vibrates in synchronism with the fluctuation of the arc of the high-pressure discharge lamp, and that the DC tube voltage is input to the resonance intensity detection circuit 11.

  Here, as described above, the lighting frequency f1 shifts from the region A (non-resonance region) to the region G (intensity resonance region) through the region F (non-resonance region) as the luminous flux rises (increase in tube voltage). What to do is set. Then, flickering starts when the tube voltage reaches the vicinity of the boundary between the region F (non-resonance region) and the region G (strength resonance region).

  On the other hand, the resonance intensity detection circuit 11 calculates the amplitude of the voltage fluctuation of the DC tube voltage, outputs a switching signal when the amplitude exceeds a predetermined value, and the frequency f1 at which the control circuit 10 drives and controls the switching element. Is set to be lowered by a predetermined width δf2.

  Therefore, the vicinity of the boundary between the region F (non-resonance region) and the region G (intensity resonance region) is detected by this, and control is performed with a new lighting frequency f2 (= f1-δf2) that remains in the region F (non-resonance region). The circuit 10 drives and controls each switching element. The control circuit 10 maintains this frequency f2 until it receives the switching signal again. Here, the predetermined width δf2 is set to be smaller than the frequency width of the region F (non-resonant region) based on the experimentally obtained region section.

  In this case, as is apparent from the figure, since the tube voltage has not yet reached the voltage range Vs for stable lighting, it continues to increase thereafter, and again the region F (non-resonance region) and region G (intensity resonance region). The vicinity of the boundary is detected. After the detection, when a switching signal is output from the resonance intensity detection circuit 11, the control circuit 10 lowers the lighting frequency by δf2, and the frequency f3 (= f2−δf2) included in the region F (non-resonance region). The switching elements are driven and controlled. This operation is repeated until the tube voltage reaches the voltage range Vs and is saturated, and the lighting frequency fn is switched stepwise so that it always remains in the region F (non-resonant region).

  Thus, the operating point given by the tube voltage and the lighting frequency moves from the region A (non-resonant region) to the region F (non-resonant region) avoiding the resonance region, and reaches the region where stable lighting is performed. be able to.

  Although there are various methods for controlling the lighting frequency within the non-resonant region after stable lighting, there is no relation to the gist of the present invention, so that the description is omitted. However, since the lighting frequency remains in the non-resonant region even when the above operation is repeated, the above operation may be continuously executed.

  As described above, since the lighting frequency is changed in accordance with the change in the discharge state when the luminous flux rises, and the acoustic resonance phenomenon is avoided, flickering during lighting including before reaching stable lighting can be avoided. In addition, since it is not necessary to perform frequency switching for exceeding the resonance region until stable lighting is reached, it is possible to make the luminous flux rise with a more stable feeling.

Embodiment 3 FIG.
In the second embodiment, as the tube voltage increases, frequency control is performed when a frequency for transition from region A (non-resonance region) to region G (intensity resonance region) through region F (non-resonance region) is set. Explained. In the present embodiment, a control method in which the operating points given by the tube voltage and the lighting frequency follow different trajectories will be described for the same case as in the second embodiment.

  Since the circuit configuration diagram is the same as that shown in the first embodiment, a description thereof will be omitted. FIG. 4 shows a locus L3 followed by the operating point given by the tube voltage and the lighting frequency of the high pressure discharge lamp lighting device according to the present embodiment based on the partitioned areas A to G shown in FIG. , Written.

Next, the operation will be described with reference to FIGS.
The control circuit 10 drives and controls each switching element at the frequency f1 at the start, and maintains this frequency until the switching signal outputted from the resonance intensity detection circuit 11 is received. As in the fourth embodiment, the tube voltage oscillates in synchronism with the fluctuation of the arc of the high-pressure discharge lamp and that the DC tube voltage is input to the resonance intensity detection circuit 11.

  On the other hand, the resonance intensity detection circuit 11 calculates the amplitude of the voltage fluctuation of the DC tube voltage and outputs a switching signal when the amplitude exceeds a predetermined value, and the control circuit 10 controls driving of each switching element. The frequency f1 is gradually decreased. As it gradually decreases, the flickering starts again in the vicinity of the boundary between the region F (non-resonant region) and the region E (medium resonant region).

  As a result, the vicinity of the boundary between the region F (non-resonance region) and the region E (medium resonance region) is detected, and the control circuit 10 can detect a new lighting frequency f2 (= f1-fh + δf3) that remains in the region F (non-resonance region). The drive of each switching element is controlled by. Here, fh is a frequency width of the region F (non-resonant region), and δf3 is a frequency increment set smaller than the frequency width fh. Both are set based on the experimentally obtained area divisions.

  Also in this case, as is apparent from the drawing, the tube voltage does not reach the voltage range Vs for stable lighting, and therefore continues to increase.

  Here, the lighting frequency f2 is maintained for a predetermined time, during which the tube voltage increases. After being maintained for a predetermined time, the frequency is gradually decreased again using the switching signal output from the resonance intensity detection circuit 11 as a trigger. When the frequency is gradually decreased, the frequency near the boundary between the region F (non-resonant region) and the region E (medium resonance region) is obtained again. The control circuit 10 drives and controls each switching element at the lighting frequency f3 included in the region F (non-resonant region) by increasing the calculated frequency by δf3.

  This operation is repeated until the tube voltage reaches the voltage range Vs and is saturated, and the lighting frequency fn is switched stepwise so that it always remains in the region F (non-resonant region).

  As a result, the operating point given by the tube voltage and the lighting frequency moves from region A (non-resonant region) to region F (non-resonant region), avoiding the resonance region, and can reach the region of stable lighting.

  Although there are various methods for controlling the lighting frequency in the non-resonant region after the stable lighting is reached, the description is omitted because it is not related to the gist of the present invention. However, since the lighting frequency remains in the non-resonant region even if the above operation is repeated, the above operation may be continued.

  As described above, since the lighting frequency is changed in accordance with the change in the discharge state when the luminous flux rises, and the acoustic resonance phenomenon is avoided, flickering during lighting including before reaching stable lighting can be avoided. Further, it is not necessary to switch the frequency for exceeding the resonance region until stable lighting is reached, and stable lighting can be achieved, so that a more stable luminous flux rise can be achieved. Further, after reaching stable lighting, the above-described operation interval may be increased and the same control may be performed, so that the lighting frequency is always included in the region F (non-resonant region) even during stable lighting.

  In the present embodiment, when determining the lighting frequency fn (n> 2), the lighting frequency is lowered to detect the vicinity of the boundary between the region E (medium resonance region) and the region F (non-resonance region). However, conversely, the lighting frequency is increased to detect the vicinity of the boundary between the region F (non-resonance region) and the region G (intensity resonance region), and the lighting frequency fn is controlled to be lower by δf4 from the boundary. However, the same effect can be expected.

Embodiment 4 FIG.
In the second or third embodiment, the vicinity of the boundary between the region F (non-resonance region) and the region E (medium resonance region) or the region G (intensity resonance region) is detected, and a frequency corresponding to the vicinity of the boundary is slightly changed. The control method has been described in which the lighting frequency is always kept within the region F (non-resonant region). However, in the present embodiment, the lighting frequency is always within the region F (non-resonant region) without detecting the vicinity of the boundary. A control method to be described will be described.

  Since the circuit configuration diagram is the same as that shown in the first embodiment, a description thereof will be omitted. Further, FIG. 5 shows a trajectory L4 followed by the operating point given by the tube voltage and the lighting frequency of the high pressure discharge lamp lighting device according to the present embodiment based on the partitioned areas A to G shown in FIG. , Written.

  Next, the operation will be described with reference to FIGS. In the control circuit 10, an operating point given by the tube voltage and the lighting frequency draws a locus in the region F (non-resonant region) such that the lighting frequency decreases at a substantially constant change rate with respect to the increase of the tube voltage. Such a conversion formula is obtained in advance, and this formula is stored in a memory (not shown) in the control circuit 10.

  Then, it is confirmed that the tube voltage by the tube voltage detection circuit 9 is within the region F (non-resonant region), the frequency is calculated from the conversion formula stored in the memory based on the tube voltage, and the lighting frequency is Control is performed so that the calculated frequency is obtained.

  Thereby, after the operating point given by the tube voltage and the lighting frequency reaches the control F (non-resonance region), it always stays in the region F (non-resonance region) while gradually decreasing as the tube voltage increases. It will be.

  That is, it can move from region A (non-resonant region) to region F (non-resonant region), and can shift to stable lighting while avoiding the resonance region.

  Although the case of using a conversion formula has been described here, a conversion table may be prepared in advance and stored in a memory. Although there are various methods for controlling the lighting frequency in the non-resonant region after the stable lighting is reached, the description is omitted because it is not the gist of the present invention. However, since the lighting frequency remains in the non-resonant region even if the above operation is repeated, the above operation may be continued.

  As described above, since the lighting frequency is lowered according to the tube voltage to avoid the acoustic resonance phenomenon, flickering during lighting including before reaching stable lighting can be avoided.

Reference Example In Embodiments 1 to 4, flicker avoidance before stable lighting is performed by a single algorithm, but in this reference example , frequency control when the above is combined will be described.

  Since the circuit configuration diagram is the same as that shown in the first embodiment, a description thereof will be omitted. 6 to 8 follow the operating points given by the tube voltage and the lighting frequency of the high-pressure discharge lamp lighting device according to the present embodiment, based on the partitioned areas A to G shown in FIG. The trajectories L5 to L7 are written.

  Next, the operation will be described with reference to these drawings. In a state where the operating point is included in the region A (non-resonant region) and the region D (weak resonance region), the trajectories L5, L6, and L7 are controlled in the same manner as described in the first embodiment. Done.

  After the operating point moves from the region D (weak resonance region) to the region F (non-resonance region), the locus L5 is the same as that described in the second embodiment, and the locus L6 is the same as that described in the third embodiment. In addition, the locus L7 is controlled in the same way as described in the fourth embodiment.

  As a result, the operating point given by the tube voltage and the lighting frequency moves from region A (non-resonant region) to region D (weak resonance region) to region F (non-resonant region). Can be switched to stable lighting.

  It should be noted that the moment of detecting tube voltage oscillation near the boundary between the region D (weak resonance region) and the region E (medium resonance region) or the moment of passing through the region E (medium resonance region) Since the time is sufficiently short from the viewpoint of the discharge phenomenon and the visual viewpoint, flicker does not become a problem.

  As described above, since the lighting frequency is changed in accordance with the change of the discharge state at the rising of the luminous flux to avoid the acoustic resonance phenomenon, the flicker before reaching the stable lighting can be avoided.

  Further, by combining a plurality of control algorithms, it is possible to reliably avoid flicker before reaching stable lighting regardless of the width of the resonance region E (medium resonance region) or the region F (non-resonance region).

In Embodiments 1 to 4 and the reference example , the metal halide high-pressure discharge lamp having a ceramic arc tube with a rated power of 35 W has been described as an example. However, other high-pressure discharge lamps also have a frequency, a tube voltage, and an acoustic wave. If the relationship of the resonance phenomenon is similar, flicker before stable lighting can be avoided by the same control.

In the first to fourth embodiments and the reference examples , in order to prevent erroneous detection, the initial transient state (eg, discharge with argon gas) may be ignored. In this case, an algorithm that performs control based on the detection result of the resonance intensity detection circuit 11 starting from the time when the tube voltage is equal to or higher than a predetermined value or the time after starting the lighting operation is equal to or higher than the predetermined value is appropriate. .

It is a circuit block diagram of the high pressure discharge lamp lighting device which concerns on Embodiment 1 of this invention. It is a figure which shows the locus | trajectory L1 which the operating point of the high pressure discharge lamp apparatus which concerns on Embodiment 1 of this invention follows. It is a figure which shows the locus | trajectory L2 which the operating point of the high pressure discharge lamp apparatus which concerns on Embodiment 2 of this invention follows. It is a figure which shows the locus | trajectory L3 which the operating point of the high pressure discharge lamp apparatus which concerns on Embodiment 3 of this invention follows. It is a figure which shows the locus | trajectory L4 which the operating point of the high pressure discharge lamp apparatus which concerns on Embodiment 4 of this invention follows. It is a figure which shows the locus | trajectory L5 which the operating point of the high pressure discharge lamp apparatus which concerns on a reference example follows. It is a figure which shows the locus | trajectory L6 which the operating point of the high pressure discharge lamp apparatus which concerns on a reference example follows. It is a figure which shows the locus | trajectory L7 which the operating point of the high pressure discharge lamp apparatus which concerns on a reference example follows. It is a circuit block diagram of the conventional high pressure discharge lamp lighting device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 DC power supply, 2 Half bridge circuit, 3 Control circuit, 4 Load circuit, 5 Resonance capacitor, 6 Choke coil, 7 Start circuit, 8 High pressure discharge lamp, 9 Tube voltage detection circuit, 10 Control circuit, 11 Resonance intensity detection circuit

Claims (14)

And a high-pressure discharge lamp, a tube voltage detecting means for detecting the tube voltage of the high-pressure discharge lamp, a high frequency power supplying means for supplying high frequency power to the high pressure discharge lamp, the frequency of the high frequency power supplied from the high frequency power supply means A high-pressure discharge lamp that stably lights the high-pressure discharge lamp in a region predetermined by a specific frequency range having a voltage range in the vicinity of a saturation voltage during stable lighting and a non-resonant region in the voltage range. In the electric lamp lighting device, the control circuit supplies high-frequency power outside the specific frequency range at the time of stable lighting at the start of lighting, and the lighting frequency is changed to the non-resonant region according to the increase of the tube voltage until stable lighting. fit manner, the high pressure discharge lamp lighting apparatus characterized by being configured to vary the operating frequency. In the high-pressure discharge lamp, the boundary between the non-resonance region and the resonance region moves in a direction in which the frequency decreases as the tube voltage increases, and the tube is less than the voltage range even within the specific frequency range during the stable lighting. 2. The high pressure discharge lamp lighting device according to claim 1, wherein an acoustic resonance phenomenon is caused by the voltage. Resonance intensity detection means for detecting the magnitude of the fluctuation of the discharge arc due to the acoustic resonance phenomenon based on the change in the tube voltage detected by the tube voltage detection means, the resonance intensity detection means from the start of lighting until stable lighting. 2. The high pressure discharge lamp lighting device according to claim 1, wherein the lighting frequency is maintained until a fluctuation of a discharge arc exceeding a predetermined magnitude accompanying a rise in tube voltage is detected. Resonance intensity detecting means for detecting the magnitude of fluctuation of the discharge arc due to the acoustic resonance phenomenon based on the change in the tube voltage detected by the tube voltage detecting means, and the high-pressure discharge lamp has the specific frequency at the start of lighting. range minimum frequency less than the first frequency is applied as the lighting frequency, the resonance strength detecting means sway of the discharge arc which exceeds the rising accompanied to a designed size in the tube voltage until stable lighting after the lighting the when detected, the control circuit is a predetermined amount raised the lighting frequency from the first frequency, claim 1, characterized by being configured to switch to a second frequency which belongs to the specific frequency range The high pressure discharge lamp lighting device described. Wherein from the start of the lighting operation after a predetermined period of time has elapsed, it said resonance strength detecting means, when not detecting a shake of the discharge arc which exceeds a predetermined magnitude, said control circuit is forcibly the lighting frequency The high pressure discharge lamp lighting device according to claim 4, wherein the high frequency discharge lamp lighting device is configured to switch from the first frequency to the second frequency. The high pressure discharge lamp is the minimum frequency less than the first frequency of the particular frequency range at the time of lighting start is applied as the lighting frequency, the tube voltage the tube voltage detecting means after the start of lighting exceeds a predetermined value when it is detected that, or if from the start of the lighting operation is either when a predetermined time is detected that has passed, the control circuit, by a predetermined amount the lighting frequency from the first frequency The high pressure discharge lamp lighting device according to claim 1, wherein the high frequency discharge lamp lighting device is configured to be raised and switched to a second frequency belonging to the non-resonant region. Increase in the tube voltage between the control circuit, after switching to the second frequency the lighting frequency from the first frequency, in the non-resonant region, the second frequency, up to stable lighting The high pressure discharge lamp lighting device according to any one of claims 4 to 6 , wherein the high pressure discharge lamp lighting device is configured to decrease stepwise or continuously in accordance with the above. Resonance intensity detecting means for detecting the magnitude of the fluctuation of the discharge arc due to the acoustic resonance phenomenon based on the change in the tube voltage by the tube voltage detecting means, and the high-pressure discharge lamp has a specific frequency range at the start of lighting. maximum frequency greater than the first frequency is applied as the lighting frequency, wherein when the resonance strength detecting means detects the vibration of the discharge arc which exceeds a predetermined size after the start of lighting, the control circuit is a lighting frequency the The frequency is lowered by a predetermined amount from the first frequency to switch to the second frequency belonging to the non-resonant region, and thereafter, the second frequency is set in response to the increase of the tube voltage in the non-resonant region. stepwise, or high-pressure discharge lamp lighting device according to claim 1, characterized by being configured so as to continuously decrease Te. The high pressure discharge lamp is a maximum frequency greater than the first frequency of the particular frequency range at the time of lighting start is applied as the lighting frequency, the tube voltage the tube voltage detecting means after the start of lighting exceeds a predetermined value when it is detected that, or if from the start of the lighting operation is either when a predetermined time is detected that has passed, the control circuit, by a predetermined amount the lighting frequency from the first frequency The frequency is lowered to switch to the second frequency belonging to the non-resonant region, and thereafter, the second frequency is changed stepwise or continuously in the non-resonant region according to the increase of the tube voltage. The high pressure discharge lamp lighting device according to claim 1, wherein the lighting device is configured to be reduced. To decrease the second frequency in stages, with the increase of the tube voltage, when the resonance strength detecting means detects the vibration of the discharge arc which exceeds a predetermined magnitude, said control circuit, said The high pressure discharge lamp lighting device according to claim 8 or 9 , wherein the operation is performed by repeating the operation of lowering the lighting frequency by a predetermined amount. The control circuit decreases the second frequency stepwise, and when the resonance intensity detecting means detects a discharge arc fluctuation exceeding a predetermined magnitude after the decrease , the control circuit determines the lighting frequency. The high pressure discharge lamp lighting device according to claim 8 or 9 , wherein the operation of raising only a fixed amount is repeated at predetermined time intervals. The control circuit is configured to continuously reduce the second frequency by controlling the lighting frequency so as to decrease the lighting frequency at a substantially constant change rate according to the increase in the tube voltage. The high pressure discharge lamp lighting device according to claim 8 or 9 , wherein The control means applies a first frequency higher than the maximum frequency in the specific frequency range at the start of lighting to the high-pressure discharge lamp, and the tube voltage detected by the tube voltage detection means from the start of lighting to stable lighting. 2. The high pressure discharge lamp lighting device according to claim 1, wherein the lighting frequency is controlled based on a voltage so that the lighting frequency continuously decreases when the tube voltage increases. The high pressure discharge lamp is a maximum frequency greater than the first frequency of the particular frequency range at the time of lighting start is applied as the lighting frequency, as the operating frequency in response to an increase in the tube voltage falls to the non-resonant region 2. The high pressure discharge lamp lighting device according to claim 1, wherein the lighting device is configured to decrease at a substantially constant rate of change.

Images